Running OS X, Intel version... loaded up Live 6 and Guitar Rig 2.2, and I can only see the VST version of Guitar Rig. For some odd reason I'm not seeing the AU version show up, even though all of my other NI instruments/FX are being listed.
Not certain if this is a Live issue, or Guitar Rig issue, but figured I'd post it. And I did check, the .component file for Guitar Rig 2 is version 2.2.0.007, so it is up to date.
Greg