Take a look at this web site for a coupe of Hydro-Static drive builds to drive Two Wheelers with Two Wheel Drive.
http://www.hydraulicinnovations.com/index.htm

Have a look at a real 1X2 , 2X2 , constant power and
optional differential lock of a bicycle.
visit also:
www.hydrocad.blogspot.com

I had seen the motorcycles earlier - pretty cool indeed! The bicycle though,..that's awesome? Are there plans to move the pump displacement control up to a position where the rider can adjust it on the fly?

I've got a Gary Fisher bicycle similar to the one in the photo. How much $$ to retrofit? ;-)

Great job!

Yes , it is a modified gary Fisher bicycle.
It is not for sale or offering a retrofit kit.
We developed a trnasmission that fits rider's
nearly constant muscles stress that now we
are prepared to develope a commercial prototype
that will weigh less, improved performence to
fit a pedal driven pump at 60 to 90 revs with
high volumetric and mechanical efficiency ,
using the frame to locate tubing, installing
controls on steering, braking be flow restriction and more.

Here are some other Human Powered
Vehicles that the trendy are Bicycles.

GEN-DRIVE.pdf (132 KB, 92 downloads)