I happen to have a stub axle wheel from a sidecar kiddie carrier that would work. After figuring out the steering mechanics we decided it might be prudent to create a rough proof-of-concept by welding together some defunct bicycle frames. Neither of us are great shakes at welding and that's when we were saved by Curtis who happened to be in town (he hails from Rhode Island). If anybody can fabricate in steel it's Curtis. He graciously came by the shop on his last day in town and gave us a welding 101 for idiots. He also looked over our plans for the proof-of-concept and suggested some changes that would save time & frustration. Way to go Curtis. While he was doing this he was also showing another fellow (Jeff's friend John) how to build a pedal powered Jacobs Ladder (go figure).
On a tangential subject it appears that being associated with Portland has improved Curtis' chances of hooking up with the opposite sex back home......who knew that's all it took?