you mean a cheek rest for a scoped AK like this?
http://cdn3.volusion.com/vawhb.dxcnr/v/vspfiles/photos/CA-metal-adj-cheek-rest-2.jpg
if so, something like that wouldn't be all that complicated or difficult to make, from a hunk of plastic or look around the web and find one you can modify.
I don't use a scope on my AK, I just use the iron sight and so I don't need a cheek rest
but, I made a cheek rest from resin for my M-N with PU scope. the PU scope very high and I got tired of doing the "chin to stock weld" I saw in a very old soviet manual cira 1930s, of a cheek rest that a NKVD shooting team used on their PEM scoped 91, and I just copied that. now shooting my scoped M91/30 is a lot more enjoyable
http://www.hunt101.com/data/500/medium/painted_MN_cheek_rest_top_view.jpg
http://www.hunt101.com/data/500/medium/painted_MN_cheek_rest.jpg