I have been overwhelmed with comment and trackback spam of late to the point that I stopped posting for a while as I tried to deal with this problem. I noticed that Overlawyered had the same problem. It looks like Movable Type may do something about this in a future version but I had to deal with the problem now.
Basically, I had to take the brute force method of opening up every single past message and individually turning off comments and trackback and re-saving in order to get the rotten %$#@%$@%$! off my site.
I’m going to try to leave a few new posts open for a short time but it seems that the spam jerks can track down any post and flood my system with their crap.
Sorry for the inconvenience.