Dspam Appliance - repost 4

I need to have built a spam filtering appliance based on dspam. We will be rolling out this appliance to multiple sites with multiple domains, so it must be quick and easy to deploy. We use mostly Debian and CentOS so sticking to one of these is preferred. The outcome should be a dspam appliance that will allow for multiple domains to be protected, provide access to the dspam webgui, and incorporate antivirus scanning through clamav. This software will need to act as a gateway, with the ability to forward mail to more than 1 internal server when required. I would also like the option to verify addresses via LDAP into active directory, however, not all of our mail servers are AD based so I need to be able to turn this on and off per domain.