I recently added TeeChip to the list of storefronts where I sell my work.  I've broken it up into two categories here (I did the same on Teespring), since their site provides that functionality easily without creating separate accounts, one for the majority of my work, both graphic designs (like the Raven Mad and Clever Shirt) and illustrations (Desert Tree, Sun Kissed, etc.):

and one for my explicitly political pieces, which at present is just the Fairey-inspired Shame and Persist designs, but may include more down the line.  I've got an idea for a third one I'm noodling on at the moment.