I may be a little behind on this thread but Clark connect could be a very viable option for you. It functions as a firewall but there are also modules for other functions as well.
I know its Linux based ::gasp:: but let's not start that debate again.
This is, of course, if you choose to go the machine base firewall instead of an appliance based firewall.
ClarkConnect can be downloaded at www.clarkconnect.org