Cool. I like the idea of modular power too. And I just realized I may have a source of used power packs... Someone I know runs a repair/warranty depot for a big manufacturer of power tools...
Hmmm... remember the Milwaukee Tools LiIon powered '62 Chevy Bel Air on Monster Garage?
Milwaukee Electric Tool - News & Events - Press Release Archive- From V-8 to V28™ Power! - 09/12/2008