I figured you would enjoy all the same my little discovery. If it has been mentioned before I do apologize.
It seems two characters from a galaxy far, far away have bled into the Mouse Guard universe.
[edit]Oh no, no that will not do at all. Seems that I uploaded the full-sized image. Fixed.
The millenium Falcon is also amongst the skulls on this cover:
Crow
Hahahaha! That’s awesome! Took me a minute to find it.
Paws Solo!
I’ll have to keep an eye out for more StarWars easter eggs. I never noticed that one, good find Scarecrow.
I only found it because he mentioned tham on his blog somewhere…
http://davidpetersen.blogspot.com/
I spent a good hour scanning just the front cover figuring it’d be one of the eye sockets or something (I even thought I’d found it at one point, but wasn’t sure). 
It’s fairly obvious when you know where to look!
Crow
yeah, wow that is super obvious once you catch it. It stands out big time 