Question

I've seen a few designs for pedal operated generators but what I'm wondering about is a pedal operated PTO. I have the desire for a reasonably portable unit that could be used to "motorize" our grain mill, possibly power a homestead sized threshing machine, root washer, maybe even a lathe or other shop tools? The design I like best is the Rodale Energy Cycle, but I'd like for some method for making it belt-drive and adding a flywheel? Other designs out there that come close to this idea?