Today, exactly three months to the day after I first submitted my paperwork, I received a call from the Moduslink Windows Vista Upgrade Redemption center. The pleasant woman on the phone informed me that my COA and POP had been processed and approved. Praise the Gods! She said I should receive the upgrade in March. I certainly hope so.
This has been a lot harder than it should have been but it looks like it has finally been resolved. I remain hopeful the upgrade disc will ship in a timely manner.