These are not exactly what you're looking for...because this wall was skinned with 3/4" CDX. But for the niche construction itself, the theory is sort of the same:

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ABOVE: You can see where two studs were cut out for the wall to make room for the niche. This niche is about 36" wide. the wall is non load bearing, so a 2x4 on the flat was installed as the niche bottom, the middle shelf, and the niche top.

Above: The whole thing is skinned in cement board or fibercement. In this shower, the walls are cement board. thin strips of cement board are fragile, so I'll sometimes use strips of fiber cement instead to line the shelves.

ABOVE: This shows the niche shelves are pitched slightly for drainage.

Now if you were going to tile on the cement board, you need to coat the niche with a topical waterproof membrane. A commonly used on is RedGard, it's sold at Home Depot. Coat the niche well, and coat the walls surrounding the niche out about 8"-10" around the face of the niche.

Then tile.

In my case I did a Kerdi shower, so I didn't have poly between the cement board and the framing. You would.

Kerdied niche:

Tiled niche:

If it's an exterior wall, realize that in a cold climate you're eliminating insulation in that wall so your niche will be cold in winter.

Mongo

Oh, I meant to add...typical niche depth in a 2x4 cavity will net you an approximately 3-1/2" deep niche.

If you need more shelf depth, you can always make your shelves deeper so that they come out proud of the wall.

Mongo

Thank you Mongo for the example. 3-1/2" should be plenty deep for the niche I have in mind. So, it seems that we can do it. Thanks!

Mongo, those are gorgeous! I am in awe and wish I had seen this post before the niches in our final bathroom were done (using pre-formed niches.)