I was actually relieved to know that my domain problems were caused by a bad hard drive. Even though it’s time-consuming, it was a halfway easy fix after hitting up some knowledge base goodness.
Since the DC’s hard drive was dead, I had to use ntdsutil to remove the dead computer and all of its metadata from Active Directory (the article I used is here). While this was going on, I had a clean install of 2003 Server cranking out on a new disk. Once it was ready, it joined to our domain with no difficulty. The DC promo process went smoothly, and roughly 14.5 hours after the incident was reported, things were back to normal.
…and I didn’t have to crack open that bean and rice soup, either… although I might anyway.