I've finally moved this site over to Drupal. I've been working with Drupal for the past 2.5 years, and don't know a thing about hacking WordPress, so moving the site over to the tool that I know ensures that I can really own this thing and play around with it. Hopefully ReCaptcha and Mollom will mean the end of comment spam.
Migrating the site was far easier than I expected. I used an experimental 6.x version of the Wordpress Import module, and it worked well, except for one post that complained about a duplicate key. I fixed it manually by entering in the post info by hand and changing various nid references (comments, url aliases, comment counts, etc.) in the database. I could tell what tables needed to change from the error messages I was given.
Migrating the theme was a little more time-consuming, but not by much! They're both PHP, so it was a matter of consolidating all the different templates that comprise a WordPress theme into a single page.tpl.php, and swapping out some function names. It's not perfect -- the tags and submission info look clunky, and the main nav is not a proper Drupal menu -- but I'm going to redesign the site anyway, so I'll let a few eyesores stick around as incentive to get moving on it. Enjoy!