For natural sunlight, I recommend skylights. Adding a few skylights would allow natural light to flow right in. For closet space i suggest shelves in a room maybe adjacent wall near where the bathroom would be. or next to it. Can be great for bathroom and room storage as well. maybe two closets?

Here is a link that might be useful: Bathroom Remodeling in Los Angeles

Do you really want 2 separate showers, or would 1 large shower with 2 shower heads work?

I don't have time to sketch it out an upload, but what about something like this for starters (you can play with the proper dimensions):
-run a wall down the room roughly center of the 20'10" dimension, splitting it in half. Bath on the left, closet on the right.
-Put a door in the center of the new wall and vanities on either side.
-center the bedroom door on the left wall
-put toilet in separate room on top wall to the left, tub on top wall to the right of toilet room, move window so it's over tub.
-put both showers (if that's what you mean) on the bottom wall

Alternate:
-same wall splitting the room, but doors on the ends of the walls instead of center
-put showers centered along right (closet) wall, put tub in front of showers, front and center in room.
-vanities could go on either top or bottom wall, or one on each.
-toilet room in top left or bottom left corner.

Thanks for your help so far.

Kaysd, sorry for the confusion. I didnt mean two separate shower stalls, but exactly what you are proposing - one larger stall with two showers in it. In fact, even a really large "wet area" with the tub in it would work too.

I prefer that closets be accessed from the bedroom, rather than the bathroom, because I find that more convenient and I donâÂÂt want moisture getting in the closet. I like walk-in closets to be 7' wide, because that allows 2' down each side for hanging clothes (or shelves, drawers, etc.), with a 3' aisle in between (comfortable for walking, but not a lot of wasted space in the middle). I use the space at the narrow end opposite the door for shelves or a shelf and drawer combo, so you donâÂÂt have hanging clothes running into each other on the corners.

This is a quick sketch, not to scale. You would need to adjust the door and window locations. I didnâÂÂt draw in the doors for the toilet room, closet, shower, etc.
The closet has a 7' x 12' interior. The shower would be about 8' long, and 4-6' wide, depending on your preference. (You can shrink the length of the shower if you want more closet space.) I show a free-standing tub under the window, but deck-mounted would also work.

The vanity could run the whole length of the closet wall or be shorter. You could include storage tower(s) with the vanity. The vanity could also move to the wall opposite the closet wall, depending on what door placement works best from the bedroom side. There are a few open spaces where you could add shelves or closed cabinets for storage or display.

{{gwi:1490977}}

If you prefer to enter the closet from the bathroom, I can move some elements around. You could have doors into the closet from both rooms, but would lose some storage space in the closet.

If you would like to be able to go right from the bathroom into the closet you could use kaysd's drawing but move the vanity over to the opposite wall. Put in a door from the bathroom to the closet where the vanity currently is. Then, as kaysd mentions, you will have access from both but lose some storage space.

The bump out does seem the ideal spot for the toilet.

Flipping the vanity to the other side gives nice sight lines to the tub and window from the bed/bath door.

{{gwi:1490978}}

Thanks again. I am going to show these options to my wife this weekend, and hopefully we can agree on something that works. In the mean time, i have attached a picture of what we had come up with.

With regards to your suggestions, here are a few points.

From a design aesthetic, we would prefer to minimize the doors in the bedroom. we would prefer not to have two separate doors, one to the closet and one to the bathroom. rather, we would prefer to access both spaces through one common door in from the bedroom.

We would both prefer the closet to be 7', but the pop out size cannot be changed. we thought we would alleviate the problem by having a rack for shoes on one wall, so it would seem roomier. Other option are to reduct the walls to 4" instead of 6".

One quick observation, is that the plan we currently have has a lot more wall space for hanging room. I am sure my wife will concerned about losing some of that.

It looks like your plan gives you 19'-6" of hanging space on that long right wall. It also looks like there will not be a door separating closet from bathroom. I would want a door: to keep moisture out of the closet and so you are not looking at clothes on the opposite side of the room when you open the door from the bedroom to the bathroom.

I'm taking one more crack at it, based on maximizing hanging space and having the closet only open from the bathroom. This will let you keep a window on the right wall. The window on the top wall needs to move over to be in the shower, not the closet.

{{gwi:1490979}}

One more idea, this one is about the same hanging space, but much more room for drawers, shelves, and even hanging space if you really need more. That wall of built ins could also potentially contain hidden hampers, an open counter area for jewelry, almost anything really. You could even cheat the closet in enough for a row of shallow storage there if that would be useful, for things like shoes, purses, hanging ties, belts, etc...

If you place the shower head right, you could have matching transom windows along the top of the shower and WC for lots of light. You could even put one in the closet if you wanted to.

I keep coming back to play with this one because the size is so nice to work with. (My entire master suite, including bedroom, bath and closet, is 18' x 20'.)

This plan gives you up to 26' of hanging space in the closet (more with double-hung rods), WC closer to bedroom, and nice sight line of bathtub and window from bedroom. You can make the vanity longer or add storage towers at either end. I would put built-in shelves or cabinets at the end of the WC to make it line up with side wall of closet for a cleaner look.

{{gwi:1490980}}

This one tries to maximize natural light. The windows at the top can have a mix of short and tall storage, if you want. There is also a semi-private bench area tucked away between the tub and shower to allow for toweling off. Plenty of places to hang towels too, or add a towel warmer.

Hopefully you can pick and chose what you like from all these ideas and put together something you love!

The issue with many of the above layouts is that the closet is smaller than it could be, mostly due to lots of "hallway" space in the bathroom. If you put the bath stuff at the far end, or make it L-shaped, you've got 12' for the tub. Or else you've got 4-7' spaces in front of fixtures. Nice to have, but not if it takes away from closet space. I think in a master space this size, the closet needs to be half the 15x20 space shown.

I think the OP's drawing is the best of the above ideas. Some tweaks I'd make to others' to increase closet space:

most recent kaysd: move the toilet room door to the bottom wall and make the closet 3'10" wider.

most recent williamsem: rotate the tub so it's against the top wall, slide the shower up next to the vanity/across from the tub, and extend the closet fully to the right wall, using up the otherwise wasted "hallway" space.

FWIW, we have a 10x20 master bath with an adjacent 12x18 closet and it NEVER gets steamy enough to even turn on the fan, let alone seep into the closet.

Thank you all for your help. This definitely gave us some ideas and helped us understand better what we like and want. Not sure we are there yet, but i think definitely getting closer. Attached is the latest version we came up with. Would love some feedback on this.