Released last summer in Japan for the Xbox 360 and summarily over-pimped by yours truly, G.rev's hybrid shmup-fighter hasn't shown up on any Western release lists. Until now.
Listings for Senko no Ronde Rev. X, published by Ubisoft, have appeared on mega-site Gamespot and multiple North American online retailers. All list different dates in May but all peg Ubi as the publisher.