Paul,
just a hint, but have you looked into the power requirements to drive an electric fan to sufficiently supply enough air to run any sort appreciable boost pressure on a given engine? Have you compared those power requirements to the additional drive loads for an appropriately sized alternator? I believe you will be in for an unpleasant surprise. Even more so when you consider the extra weight associated with that large of an electric motor as well as any additional batteries.
I think electrically driven forced induction has a good potential for short-term transient conditions, but to say that it take less power to drive is short sighted at best. It will take the same mechanical energy (probably more, due to conversion inefficiences) from the engine to drive the alternator to make the required electrical energy as it will to drive a mechanical supercharger. Granted, the electrical system does allow you to spread out the time when the power is generated, but only so much. Further, a turbocharger is driven by mostly wasted energy (outgoing heat and flow velocity in the exhaust system) and really only costs power in that it eliminates any exhaust scavenging effects. If ever there was such a thing as free power, the turbo is about as close as you can get.
Also, as far as component cost, I think you are grossly underestimating the costs associated with electric motors and thier controllers at the required power levels. Keep in mind the power levels required to provide the required flow at the desired pressure. A good example is on a typical Ford 5.0L engine with a centrifugal supercharger and a power output in the 400hp range, it takes somewhere in the neighborhood of another 70hp to drive that supercharger (ie, engine would be putting out 470hp in the exact same setup if it didn't have to drive the blower). Even if you cut that in half for the 200hp range you are looking at, that is still ~35hp.
Don't get me wrong, I would be overjoyed to see a functional electrically driven supercharger, but the current level of technology doesn't allow it to be anywhere near competitive with other methods of driving a compressor. The closest I have seen to a succesful system design was the "dynapac" I believe it was called. And even then, its benefits were quite limited and very expensive.
