No luck using Disk Utility in Leopard or on the install DVD. It looks like the partition is a loss.
I decided to do a "dumb copy" of my home directory to one of my other externals that I share with a Windows computer only to run into rdar://problem/5608271. I anxiously await the Leopard compatible release of SuperDuper so I can sleep soundly once again.
To anyone reading this thread, the moral of the story is: multiple backups = multiple drives. My desire to save a few coins left me without a safety net. Don't make my mistake.