OK, so this is likely unnecessary with the new patch. However, it's still full-out b!tch!n that I can play and record on the same machine with practically no loss.

I played a mixed RT/RD and MIDI song from BIAB 2009 for Mac; output through Roland SonicCell (provides both MIDI and audio interface through USB).
Recorded on Logic Express 8 via Alesis Multimix 12 FireWire (using Apples silly proprietary FW cable).

Absolutely perfect, no hiccups.