It's going to be very pricey because 1) shower walls will require the use of tempered glass 2) for a "true color rendition" you'll need a low-iron glass (Starphire). Here's a link -

http://www.dreamwallsglass.com/2017/05/backpainted-glass-shower-walls/

Glass is notoriously a royal pain to keep clean in a shower.

It's a myth that talc causes soap scum. It's true that many commercial soaps, like dial, have talc in them, but even if you use only organic artisanal soaps, they create soap scum, too, although they have no talc at all. Talc does make it worse, though.

Personally, I prefer dealing with soap scum to the discoloration that liquid soaps eventually cause to washcloths and such, but chacun a son gout.

In any case, have the last person to use the shower each day give it a good wipe down with a microfiber cloth, and you shouldn't have any trouble no matter what kind of soap you use.

Is the shower completely enclosed on all of the 3 sides where you would use back painted glass? This will not be cheap as that glass will need to be engineered exactly to fit together , There are lots of solid surface shower walls why not check porcelanosa for some. As for keeping the walls looking good a squeegee after every shower is a good way to do so in between weekly cleanings.

You can do granite slabs cheaper.

I had my shower/tub long wall installed with a one piece mirror years ago. The only issue I had was that there was a J channel at the bottom and I lost some of the silver on the bottom of the mirror. I think had I lacquered the back and caulked the channel I would not have had the problem.

In general with back painted glass I have seen installations fail because the mastic used affected the back paint and spots appeared where the mastic was placed.

I have to say I saw large format tiles yesterday and think they are a great solution to minimize grout.

"In general with back painted glass I have seen installations fail because the mastic used affected the back paint and spots appeared where the mastic was placed". SO true, that is why all components of the install (substrate / mastic etc.) need to be specified by the glass manufacturer...and followed.

I've been looking at the (newish) Caesarstone panels that are available for groutless shower walls and floors. If you decide against glass, you may want to take a look at them:

I have a large glass back painted backsplash behind my range. I would absolutely not want to have to keep something like that clean in a shower. It shows every splatter. It's no big deal to handle in the kitchen, but three wall's worth in a shower? No way.