Winnebago EKKO, but they're new, and pricey. Some more exotic units exist, but they're closer to truck campers. Earthroamer, for one. Very pricey, but they sometimes have used ones for sale.
Mike. Comments are anecdotal or personal opinions, and worth what you paid for them.
2018 (2017 Sprinter Cab Chassis) Navion24V + 2016 Wrangler JKU (sold @ ????)
2016 Sunstar 26HE, V10, 3V, 6 Speed (sold @ 4600 miles)
2002 Roadtrek C190P (sold @ 315,000kms)