Ciao AJ-
The Round Robins I've participated in were always first come first served, but I think your idea has merit as well. As a member of Seed Savers Exchange, I can tell you that here in Canada, we're one of the last to receive the Yearbook, usually arriving some time in March. If we're to have any chance at all of getting our seeds before we need to start them, orders must be filled out and mailed straight away. For those growing peppers, however, even in glacial zone 5, it's already too late. When do most of you have your seed saving in Fall wrapped up? That would be the time to start the mailing process, I would think. You can decide if you want it to go in geographical or order in which people sign up, but regardless, a cut-off date for signing up would probably be a good idea.