I used a modification of the Going Pro Gallery theme and integrated it with Spreadshirt.com.
That’s a useful them, but has some oddities to it. For one thing, there aren’t widgetized sidebars, which just means you have to either convert it or code whatever you want into the sidebar. Another thing about it is that I really like to have even my odd looking, off-use blogs to have a normal blog page, so I had to madify a page for that.
You can look at the original from the lnkk above and then see what I did to it here: Funny Shirts