Yesterdays I was being peged around and found pegging extremely painful when your riding with a letssay "round" friend. We wanna make a 2 seater bicycle(1 crank). I have 2 frames that are suitable for this. A late 80s GT Virtigo, and a Specialized Fatboy BMX Bike. Im leaning ot the specialized as it has 14mm drop outs and its heavy duty. Since its gonna be carryign like 400lbs on its first run. Also I'd like a bike to pick up my girlfriend in ;-)
Google "Bicycle sidehack". I had 2 of them in the 80's, when they were a bit more popular than they are now. I've even seen one that clamps on. If you have access to a saw, grinder, and welder, they're not too hard to make. Just be sure to provide clearance for your cranks, and make sure the rear wheels are absolutely lined up with each other.