Yes, the service and buy-in costs for the Sprinter really turned me off on them. I'm finding that most of my race weekends are one bike and the Zuma, which isn't a problem at all. I haven't yet installed the second Pit Bull plate in the rear because it feels really tight with two bikes mocked up back there. If I absolutely NEED to take two bikes and the scooter, I'll put one on the motote.
I've been so tied up with other stuff lately that the van project has fallen by the wayside. For the time being, it's a great one-day race hauler. I added some mirror tint from Lowe's on the inside of the rear windows to keep the gear away from prying eyes, and am planning on tackling the ventilation issues next.
Take a look at the fold up bunks used in Toy Hauler trailers. They stow flat against the wall while towing out to the dunes, then fold down into bunk beds, or a larger single bed, after the toys are unloaded. There was a place in Las Vegas that sold them as components.
Here is my setup. Bikes may be a bit smaller but same idea. I bolted etrack to the floor and have the versa hauler. I have wheel chocks that mount to the etrack and can change the config to 1 bike center, 2 bikes left and right, 1 bike right, etc...