Update about being bribed to change a merchant feedback score (see post below):

I wrote the merchant again and said he'd ignored my request for my shipping to be refunded and therefore I was going to ignore his request.

Voila! I got the refund.

And he's still getting 2 stars out of 5.

He even offered me "member pricing" on any future purchase from his web site. I just happened to need a new memory card for my camera. His member price plus shipping is more than twice the price I found on eBay for the same thing.