How do you install them without brackets? Do you mean grout them into/between tiles? Not sure how that would work.

I'm sure they're easy to keep clean and they look very nice. Thanks for the idea. I took out the vintage ceramic soap dish in my surround and will need something like this. Marble sounds pretty, but I agree these would be less obtrusive.

thanks mercurygirl,
In the end, I've decided to go with the white marble corner shelves in the shower that were cut from the same slab as was used for the adjacent tub deck. With the marble, I can seal it (continuously :) and I was also a bit worried about the glass getting grotty too.

They will be installed without brackets - the tile I'm using is Walker Zanger Tiberon, it's handmade and 1/2" thick, and the marble shelves will be installed with the tiles beneath it cut to accomodate the shape of the tile. The tiles that rest on top of that shelf will be whole tiles. It's a very classic, Beaux-Arts influenced tile design and I just love it. Of course I'll post photos when it is finished.

My tile guys says that although the 1/2" tile helps a bit to support, he could do the same with a standard tile. Mortar is strong stuff!