you'll need (for security reasons) to find a way to modify the conference context to stop managers / agents from listening in on rooms they do not own (for instance the room with 8600071 has a manager who "accidentally" dial 8600051 and listens to a conversation or two for a while). this has been a problem for multi-tenant installs for those who have tried them. not usually on day one with "newbies", but eventually in almost all cases.
i'll be interested to see if you find a resolution for that
then, of course, whether you can get your box OVER 25 agents (since an 8 core xeon should be able to handle 50 agents in a non virtual environment, that's only 50% capacity ...)
and even better would be the ability to cluster ... that would be a neat trick