resume discovered by supererogatory for the lead engineer on the project, showed him commence work in February 2010. He is then made Senior Engineer on an "unannounced" project 3 months later in May 2010.
Naturally, we know next to nothing about the game other than its title. It appeared to utilize the UnrealEngine, and used Kinect for "realtime motion capture, analysis and playback".
Portal lead designer Kim Swift joined Airtight Games back in December 2009 to work on an "incredibly innovative new title" in "new and broader gaming markets", though this title likely isn't it.
Sadly, we can't say for certain whether DancePants still even exists. It may have evolved into something else entirely, or dropped in favor of a better project. If it does exist -- or any other Kinect project Airtight Games might be working on -- next months E3 expo is a likely time for an unveiling. We'll keep you up to date!