This was all a huge help. I'm still at the looking online/imagining phase. Hoping to go take a peek at a few (that unfortunately I'm pretty sure I won't be buying) just to get a hands on feel for the layout.
The information about the battery compartment is really helpful. I'm very tall, so I've accepted the fact that I won't find one that I'll actually be able to stand up in. Which is fine and all, but it did raise the question of how in the world I would make a shower useable. I assumed I would just have to shower sitting down, but if there's a possibility of dropping the floor to actually have a tall enough shower then that certainly may well be worth the trouble there.
Thanks again for all the useful info. I'll be following along, probably with more questions (likely even some stupid ones) and look forward to seeing what you come up with.