Now that I've been waiting for almost 9 months, and still nothing, I finally took the initiative and started chasing these people down for the prize.
I filed a complaint with the Washington state consumer affairs bureau, and wrote a letter to Alaska's CEO, sending along a printout of my prize-winning email. I mentioned that the lack of prizing and communication reflects very poorly on the company. Contacting ePrize gets me nowhere; they ignored me 5 times already.
I'll keep everybody up to date on my developments regarding this prize.