The seats in school buses are basically junk, I drive em! They are about the same as found in many class c's. my winnebago has "spring flex/steel" swivel seats and I dont like them. Wish I could find out if seats from a F350 would fit particularly the fully adjustable.
The bus air seats require a air source so unless in a class A with air brakes good luck. but even these leave a lot to be desired. My current bus has a lumbar support that is about 1/2 way up my back so offers little. The seat base has limited fore/aft and does adjust up down but again thats about it. The seat back does not go back far enough and keeps you too upright to do any good.
I would suggest looking for fully adjustable electric seats out of a late model pickup. i really dont know why the manuf's leave the driver area in such a primitive state. The Jsyco Melbourne has fully adjustable seats but that was about the only 1 I found with them.