It took us a LOT longer than expected to track down payment from everyone, and some people still haven't made good on their orders. These orders will be canceled as of Sunday, so that I can proceed with submitting the spreadsheet to the T-shirt manufacturers. I don't know how long printing will take, but will let you know once I have an estimate.
After shirts exist, they'll need to be shipped. This is going to mean a MASSIVE shipping party, probably at my house; volunteers will be solicited. Because we'll be doing it all by hand, I expect that mailing everything may take two to three weeks. Again, I'll keep you posted.
But that's the situation. Next time I do something like this, I may require payment immediately, to prevent a few absences from delaying the whole field trip.