Another bath inside whower idea: factory window shower - the BEST idea! Imagine this done huge-Japanese-bathroom style with an old claw-foot tub in an oversized shower, so you could have overflowy baths in a shower the size of a small room.
I love the arch and the bench in the shower. Can frost or use glass blocks on windows if privacy is an issue. I would use a different/larger tile on the back wall and ceiling of the shower. Bench idea in the shower.