I'm considering upgrades to the tandems we use for riding with the kids, and wondering about my crank length options. I might have to buy another pair of crank shorteners, but I'm not crazy about them as a solution because the space the pedals out so far for an already short rider. Who sells stoker cranks in short lengths? Are there any inexpensive options out there? Sometimes I think it might be cheaper to buy two inexpensive road cranks and go single side drive.