Poking around various tools, I was unable to initiate any kind of recovery as the database couldn't even get to any of it's checkpoints. The recovery tools literally mocked me with messages of "You forgot to give the arguments! Please see bin/mysqlcheck --help" as I tried to divine the right set of switches. Thanks guys.
Digging through some mailing lists, this sentence caught my attention:
There is little hope of recovering your tables. You should resort to a backup and upgrade to 4.0.13.This doesn't make me eager to stick gigabytes of data into it. I think I'll switch back to Postgres for now. There's been a Postgres database running non-stop in my closet for the past 3 years.
# — 26 May, 2005