The solution I've settled upon is to create a second LJ account just for tweets. It's datan0de_tweets. Feel free to follow or not. I'm not sure that the Twitter/LJ connection actually captures all Twitter activity, but since I know that Twitter doesn't permanently archive it's at least better than nothing. So datan0de_tweets should ideally have one post per day, with the first 10 tweets visible and the rest behind a cut.
Kudos to emanix for the elegant solution!
I'm still not abandoning this LJ! I just had so much life happening lately that I've had no time to properly document it! Not really a bad problem to have. :-)