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!