My time is short at the moment, so if you want to get this going my feelings will not be hurt
My initial thought was to do something similar to the calendar contest, but smaller, in which we have competing designs for people to vote on. Not sure if this is required or not. It could be that we could just have a number of designs, and people who want one or more shirts can order as they see fit. Not sur eabout the logistics of that vis-a-vis costs. Judy might be able to weigh in.
All of that was my secret plan to avoid getting a design in "rat fink" style, which I truly do not like