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.
Factory windows add a vintage industrial note to the bath -- coolest shower ever. If I could have a separate shower/tub downstairs in the en suite, that is awesome. But isn't this the most awesome upcycled window idea?
30 Luxury Shower Designs Demonstrating Latest Trends in Modern Bathrooms