Hey Paris,
Are you talking about making a mass quantity run on shirts? I was thinkin' about making my own shirt once using that iron-on paper that you can get at OfficeMax or most computer supply places. It's a paper that you can print on from your home printer and then transfer onto a t-shirt using an iron.
By using this method each shirt could be customized - notice my avatar in the mockups for my shirt below:
FRONT:
http://mywebpage.netscape.com/JoeAtA...irts-front.gif
BACK:
http://mywebpage.netscape.com/JoeAtA...hirts-back.gif
I haven't come up with a design I'm happy with myself yet, but it's another option you might want to consider.