Why not just make it a largeish van like a long, tall Sprinter? All electric will make everything work more reliably and way more practical and cheaper(eventually).
These are definitely being done, but in many cases, the well-done ones cost more than a trailer home. Look up some of the van life channels on You Tube; most of them have early videos detailing the cost outlays required. It's a lot easier to get a loan of $90k for something that technically qualifies as a home vs. a loan of $150k+ for what the bank considers a recreational vehicle.