Mike just headed out the door for lunch, and on his way he stopped by to tell me that he'd run some timing tests on the production server and that disk performance seems just fine. Hopefully he'll jump in and tell us what he did. But anyway, it doesn't look like that's the problem.
It seems to me that it's got to have something to do with Postgres, if running a vacuum analyze could adversely affect performance by that much. But I'm definitely open to hearing reasons why that's a false assumption. ;)
Thanks!