Check the link below. We have a couple from them and are pleased.

-Babka

Here is a link that might be useful: Signature Hdw. Registers

Thanks! They have a great selection. I don't think any of them are flush mount though because they all have louvers which uses a small gear to open/close. I think the only true flush mounts are the wood ones. I think I may have to go that route and paint it to match the tiles. Else I will have to shave the door which I really don't want to do. I hate when the doors have so much space between them and the floors. The old part of our house had carpet when we moved in but we took it out to reveal beautiful hardwood floors. Problem is the doors are all short. It's fine, just not the best way to go.

Have you tried Floor Register Resources? They have a number that you cannot adjust the flow, so that makes them a bit flatter.

There is also Reggio Register. From their FAQs:
Can your grilles be flush mounted into the floor?
Yes. All cast iron, brass, aluminum and zinc grilles can be recessed into the floor but only during a new construction or modification of an existing hole. We recommend you wait to receive the grille then use it as its own template.

This post was edited by dekeoboe on Sat, May 4, 13 at 22:13

The part that opens the louvers is flush with the register, i.e. it doesn't stick up above the register. I just measured my floor register and it is 3/8" thick on the part that rests on the floor. Does your door have less clearance than 3/8"? The wood ones we have in our bedroom floors are much thicker, more like 1/2". Enough to trip over sometimes. My floor register is right behind a chair in our kitchen, and the chair gets dragged over it all the time going in and out, so 3/8" is very little. Our old one had a wheel that stuck up above the face of the register. That wasn't good.

I hope you find a solution. Sorry I couldn't help.

-Babka

As dekeoboe mentioned in the above post, it is the same thing with the wood registers. They need to be installed when the flooring is being laid, they can't be retrofitted unfortunately. Which is why we have a beautiful oil rubbed bronze one in our dining room, cuz I thought of it too late, but nice flush wood ones in the rest of the house!

Oh, and BTW, the wood part that you see doesn't adjust, but it pulls out, and there is a plastic part underneath that can open or close.

I have heard the same thing about needing a small air gap below a BR door, but can't convince DH!

Thanks so much! Esp for the reference to air flow. It makes complete sense and is why another part of our house has bad air/heat flow. All the doors are random - and the ones with very little gap are highly pressurized (you have to pull the door close with 2 hands!). I did find a simple decorative metal grill at Home Depot much like the online ones (with the benefit that I picked it up today) that is about 3/8" high that will work. We will have to shave the door, but it will be fine. Thanks!!

Rejuvenation also makes flush registers that you can order with or without the louvers--they're pricey, but beautiful and might solve your problem, if one of the sizes works and you want to try something that won't require shaving the door. Good luck!