Since recent (with the very great help of Ion-Mihai Tetu, a fellow FreeBSD committer and developer for dspam) we (JR-Hosting) are running our anti-spam infrastructure on DSPAM. We stopped using SpamAssassin after some testing and resolving problems. The interesting fact is that we share most directories through nullfs so that both the webjail and the mailjail share data and our users are able to modify settings, see their stats etc. Very great and after overcoming our issues (local delivery was not OK in the beginning and the webjail was not able to properly use the MySQL database backend at first, which was odd because the main system WAS looking into it and the webjail wasn’t), it works just fine. Ofcourse it is still learning but it seems that it finds spam efficiently and quick, and it’s footprint is much much lower then SpamAssassin was. I might want to figure out how to run the daemonized version as per advise of Ion-Mihai, till then it works as a deliveryagent.
I am writing a ‘hosting environment howto’ (or something that will largely look like that) in which I will write about the setup as well.
English 
Nederlands
I tried and gave up on dspam+mysql, so would be very interested to see how you got things going. All in all, i found dspams documentation wanting.
Dear Dean,
Didn’t it work for you? or what kind of errors are you running into? I might be able to advise or help
The documentation isn’t that well spread I think, but if more people are going to use it, it will find it’s way
Very good your tip!