My 2005 Winnebago Itasca Spirit 24V has about a 4 inch stepup from the cab floor to the coach floor.
What this means is I have seven (7) taller than normal outside storage cabinets for more capacity and ease of access for stored items ... including coach components such as plumbing valves, the generator, and the propane tank. In addition there are two (2) three inch high and twelve inch wide storage areas that go laterally across the coach floor width underneath it's floor tucked between the top of the Ford chassis frame members and the bottom side of the coach floor. These two storage areas are excellent for storing long items such as shovels, brooms, fishing poles, beach umbrellas, spare sewage hoses, etc..
What this also means is it's about impossible to usefully install an aftermarket swivel seat base under the passenger side cab seat so that the seat can be rotated to face back into the coach for a better seating arrangement.
I call this a "basement design" Class C ... which might not be too common in modern Class C motorhomes. It's all about trade-offs regarding what is most important to the owners. For us, the improved storage capacity and versatility in a small Class C is priceless.