Canuck Librarian recently posted that the Librarian Gear store is back in operation as well as listing a couple other places to get library-related swag. 

I'd also add CafePress to the list although I'm not sure how good of quality their stuff is - I've never ordered from them but have heard mixed reviews.  Hmm, Cafe Press allows you to create your own designs.  Maybe I should start a sideline?  In that case, I'm sure their quality is top-notch!