I know it is probably a lot of work for Ross, but I think the Skype games are a good idea. Short fiction would be interesting, but I don't think I would be that compelled to donate fore it (i.e. would view it more as a "bonus" on top of the other incentives), but that could just be me. I can't think of anything else off the top of my head that would interest me personally, but as far as random ideas go I had two more. I don't know if gaming conventions are at all like E3 as far as swag goes, but if you pick up a lot of that you could potentially kick some of that back (but then again that might have legal implications as far as "selling" it). Or, and this one is kind of really out there, I know Mike and Jerry from Penny Arcade auctioned the dice they used in recording the DnD podcasts, so you could do dice or something (granted you don't carry the same weight as the two of them, but as far as in the "RPPR community" it may work)...
So yeah, weird stuff I know, but it might trigger and idea for someone...