The rub ...
The Jeep bike is manufactured by Christini. The reason the technology has not caught on in my opinion is:
a) It's proprietary. And it really has to be if Christini wants to get paid for his work.
b) It requires a specific tube shape for the shaft that probably is not that visually appealing.
c) In most conditions, skill will do the same job as the front wheel drive.
Once you "get good" you do not an AWD drive bike except for in mud (in which case you shouldn't be riding anyway).