My two favorite pop tops I have ever seen were a late '80s Toyota 4x4 van and an '89 Suburban 4x4. I'd pay good money for either of them if I could find one, but I've only ever seen one example of each.
Holy crap, GTRV is still around! I'm guessing they could convert a Caravan for you, but you'd probably have to get your wallet warmed up. I wonder if they still have the molds for all the fiberglass from the '90s?
Chassis