The pedal drive system is called the Mirage Drive system, I think.
I hope to get one of those this year sometime. I first saw them being used around Maui...I saw a couple of kayaks cruising by at a pretty good clip, and then realized THEY WEREN'T PADDLING!! Cool!

A member of our fishing club has one of these, and I tried it out last year on a local reservoir. Works GREAT! What I like is that you can fish or troll by pedaling, using your hands free to work the rods (s). Should also work nice for the river!