I looked at the Colorado Campervans website you linked. Nice. Sort of like Sportsmobile but maybe a bit simpler interiors which I think is maybe good. You might ask on Expedition Portal if anybody has one. I have not seen any here in California; this is definitely Sportsmobile country.
The
Sportsmobile website has tons of plans and an online design tool. They have a branch in Texas and sometimes have used SMB's for sale. Also, there are tons of vanlife build videos on YouTube.
The trouble with the custom build brands is that the design is pretty much all you see until the day you pick up the finished item. You could build yourself a cardboard mockup, but it's still not like going to a dealer and testing to see if your aging bones can get in and out of what seems like a great design on paper. I spent several hours last weekend doing just that on some Class B's which had been on the short list for my next RV (in a couple of years, but early starts are needed in this business) and in the process eliminated most of them.
BTW, some of my short-list B's might interest you: Roadtrek Zion, Travato 59G or 59K, maybe Hymer, maybe some of the new models on the Ford Transit chassis. They mostly have solar or generators and large battery banks, often have small electric refrigerators.
As to the AC/DC refrigerator, I'd vote yes. You have enough experience with solar to know how to size a system for that. Read posts on RV.net and also on Mello Mike's Truck Camper Adventure for some analyses of pros and cons of the compressor frig. Also, Expedition Portal, which did an evaluation article on them last fall. I have added a tiny portable Dometic compressor frig to my equipment for those times when the 3-way refuses to cool in hot weather. I am very happy with it. It cools quickly, stays cold, and uses very little power.
Good luck with your search!