Hope you're not holding your breath for a sequel to Kameo: Elements of Power. According to a CVG report, a follow-up to the Xbox 360 launch title was under development at Rare, but has since been canceled in favor of freeing up resources for the Project Natal launch.
In fact, CVG's sources stated that other Rare franchises also had sequels in the works, and they've all arrived at similar fates as Kameo 2. They didn't specify exactly which series had gotten the axe, but it's entirely possible that there were plans for a new Perfect Dark, Banjo-Kazooie, or Killer Instinct that will never see the light of day.
Though Rare's newfound focus on supporting Project Natal is partially to blame for the cancelations, CVG's insider also cites poor sales of the original Kameo as another reason for the abandoned sequel. And, honestly, were there really that many people who were looking forward to revisiting that world in the first place?