Agree that it's awesome. I already did way back... In this episode almost everything other than the main characters are cameos: the tshirt prints, shops, background extras, and even the movie posters. I had to be creative to place the non human characters somewhere in the episode. Some cameos appeared in the future episodes as well. In earlier parts, some of the comic banners appear on the racetrack as ad board.
Here's the old thread where I asked people if they want their characters to appear in my comic. All the pictures in the thread seemed to be gone now though.