I don't know of any vans or suvs that aren't more prone to rollover than a comparable car, not counting vehicles designed to be harder to roll over.
ford 15 passenger vans are very prone to rolling over. especially if not loaded properly. the cg is at the top of the steering wheel when these are fully loaded. i would imagine that the chevys are about the same.
suv's are mostly built on truck chassis, and the way they're built will raise the cg, thus making them more prone to rollovers.
in the case of the early explorers though, that was all on ford.........