Electric Bikes

Every once in a while the idea comes back... build a hybrid bicycle (pedal power/electric). I have some ideas, so I might as well write them down... Someone, somewhere, somehow having more free time, more free parts at hand and more talent could build it.
In my opinion the best way is to upgrade a recumbent tricycle, the front wheels are free-wheels and tilt slightly when you turn, they could be provided with brakes.
Auxiliary power (i.e. Electric, yes main power is pedal power) is provided to the sole traction wheel in the back. Either inside the hub, or in the chain, or even using a auxiliary wheel connected (on demand) to the main wheel.
I found some electric bikes site that also sell conversion kits and just the parts, although they do not provide much detail about the type of motor (DC series, parallel or separate excitation, AC synchronous, asynchronous/induction). I found it a bit expensive but I must agree that, at least according to the pictures, the motoring block appears well built the planetary gear is always expensive and the motor is cramped inside the hub.
Then I found some "recumbent designs" here, here, here, some electric recumbent here, a list of sites related here, an finally a "Hack a day" page.
Well the ideas have been written, now I need some time, finish all the other million projects, survive the credit crunch, wait for my bank not to go bust (or be nationalized) and pray for the best....