So the cpu spikes I was seeing on the activity viewer on my 1.5gig PB seem to be caused by Bidule. I can't seem to replicate this behavior with any other application. Live 6 with SL actually works better. The cpu spikes were creating dropouts and audio glitches that are unacceptable for live work. The flexible routing in Bidule is beyond cool, but the glitches make it unuseable, for me anyway.
I tried raising the audio buffer on both Bidule and/or the interface. But all that did was increase latency beyond playable levels.
My laptop looping experiment has failed miserably. Maybe when I can get a faster machine I'll go back.