|Wallpaper by MegaSweet - via deviantART|
It seems that this issue has been resolved!
The original design was actually an entry submitted to the WeLoveFine t-shirt contest, which MightyFine, manufacturer of the adult Friendship is Magic tee's, then purchased from the fan who entered it and turned into a shirt to be sold at Hot Topic. Seems a bit fishy to me, especially since the winner of that contest has yet to be announced.
The t-shirt has officially been put on hold and has been pulled from Hot Topic's website, and soon from their stores as well.
You can read more about it on Equestria Daily and the related links.