Ran across this information showing that low-floor FWD ProMaster should be much easier to pull off than a RWD Mercedes Sprinter.
It appears these guys have been building low-floor chassis based on Ducato for some time, and now seem ready to expand to USA version with ProMaster. There is a pdf download in English for ProMaster van. The compact air suspension that allows tandem rear axles is interesting, although I can’t tell how axle movement is controlled.
Youtube is a short overview based on pictures:
You can see pictures in more detail on their European web site by going to “FOTOS”
Or go to photos directly. Must click on photo to see entire view which is much bigger (at least on my computer):
Specs indicate roughly 16-inch floor height, which would leave about 12 inches of ground clearance – plenty for road use. Doing a similar chassis modification on a van 90-inches tall (low-roof ProMaster) would leave plenty of headroom for a man my height to stand and walk around. May not be worth it, but it shows it can be done.
Exhaust is indeed routed out the side to simplify chassis; which appears a lot like a low floor trailer. Basically that’s all it is since there is no drivetrain.