Thanks for the input rambler...
Trigger officially pulled... going with the 6 Core 3.33GHz Mac Pro, 24GB RAM. HD|Native + OMNI, Presonus FaderPort, UAD-2 QUAD (got an offer I couldn't refuse). Will probably buy the Neve plugin bundle for the UAD.
Still looking at Vienna Ensemble Pro to help spread the load too. I also only just found out about the Kontakt Memory Server last night... why wasn't I using this before? :/
Will post a new thread detailing my experience once I have it all running, and hopefully not too many troubleshooting threads
Cheers,
Brad.