Before I bought the motor home I took a ford extended van and had my buddy who owns a body shop turn it into the ultimate tailgate limo. I ordered custom seating from a company in California who deals with trucks, vans, and RV's. They have a great selection, great prices, and quality material and they have all the seat belt set ups etc. Also, you can call the service dept for specific questions and dimensions etc and they are very knowledgeable.
Discount van and truck is the name and here is the URL
RV Furniture,Commercial Truck,Van Seats,SUV Truck Seats,Van Tops
Hope this helps