I've bought shirts from this gal in the past. They are good quality and have lasted me a long time. The designs are pretty artistic, and if you're like me, you just can't have enough turtle shirts:
http://whatdidyoubringme.homestead.com/files/Tshirts/Herp/reptile/Reptile_turtles.htm
http://whatdidyoubringme.homestead.com/files/Tshirts/Herp/reptile/Reptile_turtles.htm