I have no insight whatsoever into OSSV development plans and/or roadmaps, but just guessing - I seriously doubt it will ever support IA64.
Itanium is simply too low in numbers on the market in my opinion:
http://en.wikipedia.org/wiki/Itanium#Market_share
According to Gartner Inc., the total number of Itanium servers sold by all vendors in 2007 was about 55,000. This compares with 417,000 RISC servers (spread across all RISC vendors) and 8.4 million x86 servers.
Regards,
Radek