After speaking to a GameStop employee, I was able to get a date out of him: October 7th. He also indicated that this would be a one day, and possibly one hour, event in which their preorders will be sold out until they receive their shipment at launch.
Whether or not this is true is beyond me, but I do believe that the last bit of information has presented itself. When I went to check GameStop's Wii page, I noticed that there is now, in big, bold letters, a message that says "Online console preorder information coming soon!".
This could mean they intend to send the e-mails out Friday the 6th to prepare everyone for a Saturday preorder event.
For anyone interested, your best bet would be to call GameStop and ask specifically whether or not this is the date, because I'm betting that by now the employees have recieved the memo.