Just surfing Instagram for cool van pics I came across a van outfitter in San Diego who, in addition to building complete vans, also sell interior kits for vans. These kits look like a good option for DIYers who don’t want to build each component from scratch. They sell everything from insulation/walls to bed platforms to cabinets. They currently only have these kits for the Sprinter vans but I’ve seen a pic of a complete build out of a new Transit so I’m assuming that they are developing kits for other platforms as well.
I have no personal experience with this company but their products look well made and they even supply installation instructions for DIYers.
You can check them out at:
http://www.rbcomponents.com
~Peter