www.sportsmobile.com
These guys will custom build a conversion van/camper and have an Austin location. My dad bought a Ford 1 ton van with a 7.5 V8 from them in the 90s when he retired and we borrowed it often for travel in the 2000s. They are great travel vehicles.
His had a flush toilet, and that was SO convenient on road trips not having to look for a bathroom and not even having to stop unless the driver had the need. In addition, a microwave on an inverter meant hot meals on the road if wanted. The van fits in a standard parking place and doesn't look like a camper/RV for when dealing with nosey HOAs. In my dads van, the windows were placed such that blind spots were minimal when driving, so with planning, you can avoid that issue
Sportsmobile converts Fords, GMs, and Ram. Personally, i think the old school GM is the way to go with the big V8 and likely more reliable than the others.