there are actually some knock off types on horse.com They are usually a flat leather noseband with long shanks..... is this the type you are looking for? Does it have to be sleister brand? (those are expensive!!)
This Sleister retails for $60+
This knock off on horse.com is $30!
I'm sure there are subtle differences...the sleister has 9.5" shanks, the fakester has 8" shanks... but would probably get the job done