In Chewelah, WA they have a system where the grower goes
online once per week and tells them what he expects to harvest next week. It is then put online for consumers to order from. On Monday, they send the farmer an email to tell him the quantities ordered. Tuesday, he must deliver it (to one location) in town (between 11:00 & 1:00), and receives a check for his produce.
http://www.localharvest.org/chewelah-valley-fresh-market-M52725
Great system for both producer & consumer.