Wow! That's an incredibly generous offer, one I can't imagine discouraging. I think whatever charity you choose, it should be one that makes both you and the majority of the community comfortable. If you'd like to offer a poll on the community, I would consider it on-topic. Also, I haven't clicked any of the links above, but are any of them international? We have people from all around the world participating here, although I can also understand wanting your dollars staying within the country. I guess it depends on how far you want to dangle this wonderful carrot. 40 Family Fest pieces would certainly be a successful fest!
Um...I think I'll be quiet now, because this is your idea and I think it's a terrific one for you (meaning, any contribution to the fest is fabulous, even comments on the entries). If there's any questions or issues, I'll do my best with them. I just want everyone to keep in mind that this is unprecedented here, but there's never any bad time to donate to charity! *HUGS*