Laidback used to sell those shirts over on the M5Board. He also has a MCoupe (and is part of Mfest), so he is on other forums. He was still selling them early last year, but not sure about how.
Here is the link from M5Board, but doesn't look like any activity in the last year.
http://www.m5board.com/vbulletin/sal...-shirts-8.html