+1 for Sportsmobile. They put different tops on Ford and Chevy vans. The Sprinter is already tall, so I don't think they'd put a pop top on that, but the other "regular" vans they do.
I know the penthouse top has a 6'10" ceiling height. I'm 6'-0" tall and I loved the height of their penthouse. The other "fixed" toppers are lower IIRC.
Current Project: Design Phase of a DIY "Sportsmobile" in Ford E-350 EB, to include: L-shaped sofa/bed, Storage cabinets, Sink, water heater, porta-potti, 2 AGM, solar, hydronic heat, attic fan, propane, portable frig...