These questions are always interesting.
Can I ask a parallel question?
Since you are going to the trouble of putting your CUCM cluster there, and your CUCM PG, why would you not also put your CVP combo boxes (call Server, VXML server, media store) there, talking to the PG (PG Generic with PIM for CUCM, PIMs for CVPs).
How many combo boxes were you needing for the volume?
Regards,
Geoff