Matt Mower mailed me the other day asking if I could have his blessing for his Radio TrackBack in Python, as he looked at my TBPY when he wrote it. I'm happy to see it, especially as it's already working on his weblog.
The only thing better would be if you could get a combined RSS feed for both the comments and trackbacks of a particular item. I can't really claim to have used such a thing here, but here I get email whenever someone comments or trackbacks, and I have used such a thing in the past (a thread of Phil Ringnalda's comes to mind). Unfortunately you can't even get an RSS feed of your comments with ... but it sounds like Matt's TrackBack would fit pretty well into PyCS, which does provide it.
Wow, I didn't realize PyCS and PyDS do ACL for blog locations. That's awesome. That and LiveJournal are the only servers to do that, as far as I know. (I'd still like to do the secure comment/post thing, though, as that'd use public-key encryption for the authentication mechanism. It looks like this makes you give out yet another password, and only you the weblog author can control what that password is, which is no fun for the holder of the password.)