This site - logo-es.com - sells allegedly original logos, but I have found there three (there might be more :-) ) works of mine that I sell non-exclusively on several microstock sites.
If you are into logos/icons, I would suggest you check if any of your work there as well.
i have already filed a DMCA complaint to GoDaddy that host the site, if you find any of your work there and wish to do the same, here are the instructions:
newbielink:http://www.godaddy.com/agreements/ShowDoc.aspx?pageid=tradmark_copy [nonactive]