My wife and actually currently sleep sideways (or closer to diagonal really) in the back of our old 1997 Dodge Conversion Van now. I'm not exactly sure how wide it is, but I know its several inches narrower than the promaster. And I am actually 6'2" but do OK on that bed (a fold down couch) so my bed design would definitely be an upgrade.
I've actually spoke with several upfitters.
Started with Sportsmobile, because I had owned one before, and though it was not what I would call real "high end", it served its purpose, worked, and held up well. But after one or two short conversations with them, I found that they were not very flexible, and just wanted to use their prefabbed furniture, floorplans, and accessories.
I then met up with a guy who had a Promaster built by Morehead designs in N.C., and really liked the methods, ingenuity, design and craftsmanship of his rig. They were also willing to do the work in phases, or allow me to do some parts of the work while they did others.. But after speaking with the company a few times, I found that even for a basic conversion, we were talking 80,000, and that was short many major amenities, Like real water tanks, and a generator.
I then found a place called Florida RV Sales and Service, who seem to be more flexible and more excited to do something different than either of the other two, but the more we get in to the details, the higher the price gets... It is slowly sinking in that its just not gonna be cheap to have someone build a quality rig; it is very labor intensive, and anyone who is worth their salt, should make a good buck for his craftsmanship. It looks like it would cost me at least 90 to 100,000 to get a good quality complete rig done by any of these upfitters. They are all hundreds of miles from me..
Then there is the Travato that keeps tempting me at around $70,000 with even MORE bells and whistles than I really need. (and assembly line quality that can be scary)
I'm thinking I could build my own rig for under $55,000... I would know how it was done, and I would not skimp on material or workmanship. It would be nice to spread out the cost over the course of the construction, and REALLY GREAT to build everything JUST the way I want it... But I just don't know if I have the time and talent and to get it done... (before I die)...