Meanwhile, I followed a couple leads on people who'd done the Movable Type to LiveJournal mirror trick. All of them were dead ends except for Bonk!Thud--which was an end that either ignored my email for help or never received it.
So after waffling for a while on whether to pester the guy behind Bonk!Thud--did the mail just not get through? was it caught by a spam filter? did he just set it aside?--I started working on a solution myself.
For the record, Perl is an even stranger language than I'd thought.
But after a couple days of hacking, I have modifications which do the trick, at least in basic testing. There's a couple things I'm thinking of adding--most notably some awareness of Movable Type "categories," where the system could be told to map MT categories to specific journals (i.e., mirror anything in the category "food" to the "sf_eats" community, don't mirror anything in the "scribbles" category, and mirror everything else to "chipotle"). I don't know that I'll actually take advantage of that ability, but I might, and if I do a public release for the ones and ones of other people looking for this it'd be useful.
The next trick will be finding something that lets me import from LJ to MT. You say there are scripts out on the web for that? Yes, there is. One of them, mentioned over and over again, with each link to it broken.
Of course, LiveJournal exports in XML format, which means theoretically I could just write an XSLT document to transform things to MT's import format.
Another trip to the drawing board, perhaps...
