We're doing two-sided shirts, like paramedick mentioned. A breast-pocket logo on the front (not set in stone, could be larger if it looks good) and a full logo on the back. I've also been kicking around the idea of having vendor (essentially sponsors) names on the backs of the shirts.
As for the colors, I really like the blue and the blue-gray pictured above.
Great work, and thanks for putting that together!
I've already spoken with one shirt company who I'm very familiar with and gotten good pricing, but I'm not opposed to exploring other options. It's all about quality work at the right price.
Also, when designing your logos, keep something in mind for use on the pin. We have pins every year, and the logo needs to be something that will work well with the standard pin design that we've been using over the years.
Keep the ideas coming, folks! I'm really liking what I'm seeing!