a bit more testing after the latest beta builds, no real change in performance...

Code:
/castsequence [nochanneling] Shadow Word: Pain, Vampiric Touch,Mind Blast, Mind Flay, Mind Flay,Mind Flay,Mind Blast, Mind Flay,Devouring Plague,
/cast Mindbender
about 20k on the dummy, preserving this since I don't have a toon on live to use it on right now.. Does perform solidly better than my earlier version (thanks again Leroy!)