Yeah, the only thing I'm not sure about is the amount of threads that would be like, flooding PG :( Could you possibly use just one thread, and instead of using the poll feature just have people type their result? Like, just edit the first post every week and after the voting period for that week just make a post to mark your spot, edit it the next week and start over? That way there wouldn't be so many threads floating around... XD;
I do think it's a good idea though :O Sounds fun.