Thanks again for the replies everyone! We've found a couple of models that fit the bill, like the Roadtrek Zion and Winnebago Era.
But I think we've come to the conclusion that a van is still too small for our needs currently, so we're looking at small Class C's instead.
2008 Newmar All Star 4156
Spartan Mountain Master Mid Engine Chassis with Cummins ISL 400
2005 Honda Odyssey Toad