hehe thanks, and just a heads up for money saving, this one just MIGHT be available on RIPTApparel.com sometime soon for just $10, if you follow me on tumblr (trekvix.tumblr.com) you'll see a promo with the date its set to sell if and when they decide to print it!
aha no no it all under the "parody" clause of the copyright act, the artist you linked to did just the same thing i and several others did -- trace the silhouettes of the photos of John Cleese doing his silly walks in the Monty Python skit, and then manipulate the image to look like whatever else instead of the original photos (me Doctor Who, the artist you linked to Assassin's Creed, another I know the xenomorphs from Alien, and another Kermit the frog, etc) I could never steal someone's hard work!
see my other comment! the design isn't a case of using and not acknowledging someone else's work, it would be nothing if not entirely both the things it is, which the design itself should make clear, and which I supported in the title by including both "tardis" and "silly walks"! tricky stuff this copyright business sometimes