on the battery issue, i think someone recently applied for a patent on a laptop battery with a built in connector so that it could be hooked up to the power port while removing the spent one and inserting the new.

beyond that i would just ask for this:

go back to the N800's two full size SD slots, put in a bigger ARM cpu and more ram, put in a screen thats similar to recent tablet pc ones. beyond that, dont change a thing.