April 28^th, 2002 (12:00am) - Several online retailers’ release sections now list Mace Griffin: Bounty Hunter for GameCube. The stores note that the game will be available for Nintendo’s next-generation console in early September of this year.
Mace Griffin, developed by Warthog and originally scheduled for Xbox release, is a first-person shooter with space combat elements. Players control the bounty hunter through a wide variety of missions, upgrading weapons and armor and taking out the bad guys. The game’s most advertised feature, its seamless selection of space flight areas and ground-based shooter scenarios, has made it one of the most anticipated titles for Microsoft’s next-generation console.

Crave Entertainment has not yet made announcements regarding a GameCube version of Mace Griffin: Bounty Hunter. More information in this regard is anticipated leading up to the Electronics Entertainment Expo, which begins this May in Los Angeles, California.

This was the complete news article reported on IGN.com

I think this might be a mistake becuse the game will be using the Xbox hardrive alot and we all know Cube has know HD. But also on the other hand Microsoft is loosing exclusives daily it might be some truth behind this.