I'd like to do a 2 1/2 by 3 foot mosaic panel from stained glass and install it in my shower wall (the durarock panels are not up yet). Because the glass is much thinner than the shower tile (travertine), i'm thinking of gluing it on a sheet of glass then somehow attaching the glass to the durarock.

I'm not attaching the mosaic directly to the durarock wall because of the thickness issue and I want to work horizontally, rather than vertically. I've only done direct mosaics (the first floor of my house, a backsplash etc),

Here are my questions:

-- Is glass the best medium to apply the mosaic? Should I consider something like a piece of stiff vinyl?

-- Is Weldbond waterproof enough for a shower? I was thinking of using that to glue the stained glass to whatever substrate I use.

-- Can thinset hold up the large piece of glass with the glass mosaic attached -- it will be two thicknesses of glass, plus the weight of the grout. I could grout it once it's up).

-- is there a better way to do a mosaic panel in a shower that involves using stained glass? i'm using the glass because it gives me more interesting color choices and i can easily cut it into the shapes i need.

thanks!