I'm 6'2" as well and I have had an OLD bus for quite a while. It's a 1964 Superior Coach Supercruiser.....the key is, it's a pusher. Anything with a center engine or a driveshaft that has to run all the way back is going to have a bit less headroom. I have about 6'4" of headroom in the center and, it's a "center-aisle conversion. As for the shower, I can just stand straight up in it and use a handheld shower-massage type nozzle....works great!
While I love my schoolie, I'd look at an actual coach conversion or, if you shop around, you can find VERY reasonably priced Prevost Coaches without slideouts that are absolutely beautiful!
Good luck!!!