Class Bs confined to a van have two choices I think for over 6'-3" height. Those with pop-tops like Sportsmobile or those with fiberglass total tops. The latter is made in Europe such as the James Page model. In the US Airstream imported and sold about 200 of them in 2005-6 and marketed as the Airstream Westfalia. More recently Advanced RV was converting the Superhigh Sprinter van with a 7 foot interior height but Mercedes Benz stopped importing that model. They might have some on sale in the pre-owned market since they take back trade-ins of their RVs and refurbish them.