Nucanoe imo has done a really great job this year. The drive system is unlike any other, its simple and looks very easy to fix in the field. It also looks as if it can be modified to fit other kayaks also. Very cool.
Oh!!!! Gosh, I am a bit slow with the pick up here. The drive Christian and others mention isn't a through-the-hull type but a whole free standing unit that fits inside an existing vessel: comprising an aluminum frame everything is mounted on, a seat and the pedal drive contraption where the propeller is mounted at the stern or transom of what will be many canoes and kayaks with no more than a little customizing in some cases. For pointed stern models, it can even be mounted off to the side as some things are on double pointed canoes. The pedal power is then transmitted down a flexible rotating cable to a propeller mounted off the back. Very cool!
I might try rigging one of these up on my Meyers Sportspal S-15 Canoe if the price is reasonable. This could really extend and improve the "fish-ability" of canoes that are often difficult to hold in position on water, certainly in the wind.
We all need to keep an eye on developments here.
If anyone sees pricing info, please post it for us all. edit (it is priced on the web page): new drive