You could alternatively just buy the shirt and wear it with just enough pride to make people believe you have a link to it but not so much pride that they question it...(An option for those who are findind it hard to find that Ivy Leage soulmate hehe)
Just don't forget what shirt you're wearing! It happened to me once: this girl started talking to me about some sort of school event and I was so confused until I looked down and realized, "Heh, I've never been to that school." XP
I mean, you could throw it up ol' school (haha puns) and still wear your middle school gym shirt. Which, incidentally, was what I was wearing to sleep anyway.