This is no challenge at all. I've DONE a steam shower (or should say REdone-- the old one was falling apart because the tile guy never waterproofed a thing-- not even the plywood seat) where they DID fabricate the glass ceiling. I'm not sure who did it, if it was just a local custom glass company, or someone who specializes in this kind of thing. If you're really interested, do a search on Point Sebago Resort, and ask to speak to the owner. Or you could ask to speak to their head of maintenence, Ed Bartlett, who is the one that actually contracted me.

The cement board fastened 8" requires all board edges to be reinforced with alkali resistant mesh and embedded in thinset. Now you can apply liquid or sheet membrane waterproofing. If sheet membranes are selected you can use it to substitute mesh tape. To simplify. You should be able to shower without any tile installed. The tile is only cosmetic. Which ever product is selected follow the manufacturers instructions. They all have a tech support line and you should use it. Your present contractor does not have the knowledge to be installing showers if he believes the cement board alone is waterproof. Red Guard, Laticrete hydraban are usually readily available liquid applied systems. I was typing and was not aware of Tundra's post.

I love the classical look of Perrin and Rowe but very difficult to get here in the states (have to get the thermostatic and then an additional valve for the 2nd rainhead) but don't love the expense and all of the metal that would be required. What's your budget, and when you mention that you don't "love" "all of the metal that would be required", what do you mean? The classic, traditional Perrin & Rowe look means an exposed system, which means lots of chrome or other metal finish. Have you looked at Rohl shower systems at faucet.com?

My contract with my GC provides that I supply the fixtures and obviously the rough stuff as well since it has to work with the fixtures. However, at some point someone who understands technical plumbing issues should be doing the purchasing or telling you exactly what to purchase. When I was selecting my shower fixtures, my designer obviously helped me with the look of the fixtures but she also explained the difference in shower valve temperature regulations - thermostatic versus pressure balance and then I decided which kind I wanted. The shower fixtures you select would then determine what rough you needed and she was responsible for ordering those. In other words I selected the style and how I wanted the end use experience to be like but she was responsible for making sure that everything necessary was provided to the GC so his plumbers could install what I wanted. So although I was providing the fixtures to the GC, someone with technical expertise was guiding me in the purchase.