I think doing it without a pricedrop would be great... They just need to keep a constant bundle going to make it more enticing through the Holidays when WiiU releases. Follow MS route with the Holiday bundles. Forza + Halo could be followed fairly easily by Sony with GT/Uncharted.
PS3 Super Slim bundled with GT5 Spec 2 and/or Uncharted 2/Uncharted Twin Pack? Would do wonders in NA/EU. Just give JP a seperate bundle, with GT5/Tokyo Jungle! Millions would be sold! MILLIONS!