Posting this information for anyone else out there that might get caught in the same situation...
When updating from OES2SP2 to OES2SP3 I patched my SLES installation, which included an update for GRUB. The upgrade replaced the stage2 file with a new one that caused the system to fail to boot.
I grabbed a known good stage2 from another server running SLES, booted into rescue mode from the SLES DVD, mounted the /boot partition, and copied stage2 in place of the new one. Although the stage2 files were the same size, their checksums did not match (hmm...possibly a corrupt file...)