There are some on Red Bubble
Shouldn't that post be on the 2000ad suspected IP infringement thread?
Along with Dandontdare's post?
I don't know what Rebellion's view on it is, but I think there's a difference in using a print on demand service for personal use and mass producing something which you then sell for a profit without the permission of the IP holder. I'd have to check the forum rules for what they say on the topic.