I really like your shirts and I don't want to scare you, but speaking as someone who made a living last year with CafePress... watch out for copyright and 'right to publicity" laws! I'm not a lawyer or anything, so this isn't legal advice, just some general basic info about selling on print-on-demand sites. Any photograph you find, unless it's your very own (taken by you) is likely owned by someone else (individual, publication, etc) and they could sue you for using it without explicit permission to use it in a money making venture (i.e. sometimes they won't care if you use it on a fan site or maybe even for a small personal run of fan club tees, but making money with it is a whole different thing. Even if you sold them for zero markup, someone like CafePress/Zazzle/Spreadshirt/etc is still making money off the sale, you know). This applies to all TRACED or even made-to-look-like an original photo versions as well. Heck, Sheppard Fairy has been threated with legal action for that famous Obama Hope poster because it was derivative and looks identical to a photo owned by the AP, not a public domain pic. Generally, only your own pic or something public domain is usable.
Except... when it involves a famous person. There's something called right to publicity. Aside from politicians (whom you can usually use pub domain pics of without worry, hence all that Obama stuff out there), celebrities have a right to their own image and likeness. Even if you draw your own MJ pic, it doesn't mean you can legally sell it on a shirt. Sucks, I know. His people (or who knows... Sony, AEG, etc... not sure) could still go after you for using his likeness without permission/license. A design of mine with Obama and a public domain pic of MLK got pulled down for violation of MLK's family's "right to publicity". And he's not even alive. I was trying to say MLK, Obama... DREAM!, but I wasn't allowed to sell it. Frustrating. Even if you see celebrity/famous related stuff on print-on-demand sites, it usually just means they haven't been caught yet. (There are some exceptions for 'fair use', like making fun of a news event, but it's touchy.) And a lot of stuff on ebay/etc is self-produced, so there's no one to catch them. Yet.
Anyway, definitely check this out to protect yourself. Maybe someone would come after you, maybe not. It's up to you whether to take the chance. And laws in different countries on this issue will probably be similar, but maybe more or less strict. I have no clue about how to get a license to sell merchandise, so maybe that's an option for you as well. I do like your designs
P.S. just noticed you edited first post to add that you're looking for MJJ Prod's number for licensing, so I guess you may have already read up on the kind of stuff I just wrote about. Sorry that I don't know who to contact. I mostly just did political designs, so never had to deal with that.
