We just added a new tshirt to our repertoire: Bugzilla tshirt
We are now using more of the American Apparel brand shirt because we did run into some supply issues with the other USA made shirt we were using. In the same vein, we are switching the Thunderbird tshirt over to American Apparel as well (Asphalt color) and you should see that shirt available soon.
We are also making good progress toward launching the International store. As soon as I have a tentative launch date, I will let everyone know.
Again, feel free to post any store suggestions you have here or send them to storesuggestions@mozillafoundation.org