I’m marking this as number 1, although I may not find anymore so this maybe be the one and only. I think this was in the Winery, in the Farmer’s Market level.
Sadly, it took me like a whole 30 seconds to figure out what it was. I saw the bullet holes in a line and thought "I didn’t do that, and no Leadhead Splicer did that… Must have been put there by the developers… hmm…" and then 20 seconds later I saw the cheese.
Now, someone should take this image and make a LOLCAT graphic.
*Cheese*
I bet they have a Wiggles easter eggs in there someplace… Maybe one of the girls drew the Wiggles dancing with Big Daddy? That is what I would draw if I could.