"Norinco had, at one point, manufactured the SKS-M, SKS-D, and MC-5D models which were engineered from the factory to accept AKM magazines without problems (though the wood stock must be relieved to accept drum magazines)."
And
"Importation of the Chinese SKS into the USA was banned in 1994."
That's why they're expensive. Actual SKS M's can't be imported anymore.
http://en.wikipedia.org/wiki/SKS
Would not mind having one of those. Dang import bans. :*(