Man ... what a great inside joke. I just noticed him.
It was a gag put in most likely by Alex Williams.
It's hard to see in the widescreen version, more visible in the pan & scan. In a wide side shot of Zigzag entering town on his little rug, at the top of the screen you see a man on a brown donkey. It's obviously Nasrudin!
The colors are slightly changed - Nasrudin's skin is lighter than it's been elsewhere and the donkey should really be light colored or orange ... but it's clearly him.
My my.
I'm attempting to put the making of Nasrudin docs up at Megaupload or something. I'll let you know if I succeed.
EDIT: I've twice failed to upload Clapperboard 2. Crap. This isn't gonna work.