The answer is: why?
OpenAntivirus in its present state seems to be very-very far from being a
reliable solution.
What about virus definition files for it? How often are they released?
What about the detection of macro viruses?
Do not forget that you are going to find a virus scanner for E-MAILS: you
have never heard about an e-mail virus one day and the next day it infects
thousands of machines.
I think Anomy in itself is a very good tool to strengthen the protection
provided by commercial antivirus programs used on the client machines: by
removing and putting all potentially dangerous contents into a quarantiane on
the server, it gives the clients time to update the virus databases. You will
also have a chance to check the suspicious contents by more than one
commercial scanners before releasing it from the quarantine.
What would OpenAntivirus provide you in its present state? Nothing but the
illusion of safety. Which might make you careless.