Just FYI, Sherryton/KeyboardStory took NyanCat after the first group buy and were the ones that ran round 2. As I didn't create the art or suggest the original idea, I had no claim to it and let them do as they pleased. However, keyboardstory.com is now gone and I think Originative is in its place. Your best bet would be to see whether those guys want to do another run of it because I have no interest in competing with them over a product that I'm sure they consider theirs more than I do.
If they say they have no interest in running another set and want me to do it, I'd happily do so though, so feel free to send me a PM if that's the case. I just graduated last weekend and am on summer break, so either I get hot on running group buys or I have to get a summer job. (Going back to grad school this fall.)