I think I know the curb your talking about. I was living in New Bedfud for the summer, i just move out neer Amherst to a little hill town.
On my commute I can leave the car in 3ed (auto) and not touch the gas for about 5 miles out of 52 round trip. So I've been getting some new ideas.
Its funny you should say that about brush-less Airplane motors, I recently thought about that exact application. Those motors seem like they could go everywhere, there small efficient, and you can get about 10hp out of some of them.
For the PS pump it could have a switch on ether side of the steering shaft so that the motor turned on only when the steering wheel was turned more than 10 degrees (or 20, or whatever). It could get complex and have a pot so that harder turns made for more power.
I guess the best way would be to take a angle sensor reading from some sort of sensor (like throttle sensor and some steel wire, maybe some zip ties) and a speed reading (splice in to somewhere) and set up a little chip to control it.
I wounder how hard it would be to make a VW pump fit under my hood....