Out of curiosity, has anyone made a front-wheel-drive recumbent with rear-wheel-steering? It would seem that having the drive train concentrated in the front of the bike (where the power is developed) would be more efficient than having to route a mile of chain to the rear wheel.

What are the physics of rear wheel steering? Would such a bike be rideable? What type of geometry would be needed to provide adequate rear-wheel-trail for stability? Does anyone make such a contraption?

The steering would probably need to be under-seat, with an offset tiller bar used to move the rear "fork." The idea is intriguing...