Victory is (sort of) served!
After calling Best Buy and bitching for the last year or so, I finally just kept saying to people "let me talk to your supervisor" until finally some guy said "I'm an executive. There is no supervisor." I told the guy everything I had done to get this rain check received, and he looked up my account on their computers. I told him it was a slap in the face to spend many thousands of dollars at a store only to be shot down when trying to redeem a raincheck for about $300 worth of stuff. So, he's sending me a $50 gift card. Not exactly as much as I had hoped for, but that's like 3 DVDs, right? Good enough. Best Buy still sucks, but this Tony guy was pretty nice. If I actually get my gift card, I may even shop there again someday.