I'm glad to see, Tom, that you still have a large interest in the future of this site and that we and itself are on your mind. Unfortunately, since there removal of a physical items store will have a negative financial effect on you too, I'd suggest adding a few more minor features to the Supporter status that wouldn't really cost anything in providing.
Perhaps some color changes in text and titles where the user who has it shows up. A little star or at least a small block of pixels next to a submission in a portal to slightly enunciate the fact that someone paying to keep the site going has submitted something (so that it is likely of at least some more value, no one who pays for this site is going to submit half-assed tests or 4-second looping animations or other spam).
Maybe the alleviation of a post-number restriction (or as much of a restriction as it is now) to the users who are fervent enough to want to actually contribute. (I'm talking, of course, about the 4 posts per thread per 30 minutes and the 4 threads per day limits; not that they have to be entirely dismissed, but merely softened for paying customers).
Maybe some added flair to a supporter's user page as well as in the chat. 25$ isn't a very large amount of money, but it's high enough to keep a whole lot of people from just giving it away for a color change, and the effect that adblocker browser addons already do for them. People do care about the site, but I think such minor, free additions could persuade them to dig a little deeper into their pockets and get something that at least feels more worthwhile for the year they're getting it.
Just a suggestion I think will yield a noticeable profit.
NG fo lyfe.