From what I have seen and understand, I think a Class B would be substantially lower than a truck/tc. But as I am sure you know, a very different camping style.
The pop-ups pretty much speak for themselves for height. It to requires a different camping style, than your current rig.
That kinda leaves you with the lowest TC without a basement. That probably means no slide and smaller holding tanks. I think your height would be pretty much what mine is plus the added height the 4x4 gives you. I kinda gather the GM 4x4 trucks are the lowest.
I think billtex height setup is probably what you would have.
Wayne