The low floor are front wheel drive. There is a shot of one showing the transfer case behind the trans. There are no pics or diagrams, nor do the pics and diagrams there show any "...shaft drive...like a motorbike..." equipment.

Regardless, these appear to be fine designs for the intended uses.

 

I can see something like the Caravan-based thing near the bottom of this page: http://www.dallassmithcorp.com/productstruck.html in a slightly less fugly version, but only because it starts out FWD. I very highly doubt that converted RWD/4wd trucks will sell very well, especially once the reliability of that t-case chain comes out. Many people still remember the fun and enjoyment brought on by the BW1339 case in the Quadra-Trac equipped Jeep Wagoneers, I know I have one that is getting due for work sitting in my driveway now. Those sent the full power through the chain, and had an offset rear axle, both front and rear outputs on the lower end of the case.
I may be seeing things, but it looks like the majority of the pickups in the lower set of pictures are photoshopped.