Great input everyone! My g/f has an exchange student that will be doing this and I'm helping her get the parts. If you were to swap out the 12v motor for a 24v or 36v one, what other components would need to change (in MetroMPG's set-up)?
FYI, we just grabbed an old exercise bike from a neighbor. Might use that to save on the woodwork (she's procrastinated and it's due ASAP). Also got a free used battery from a parts store.
Thanks!