I had difficultly finding some too, thats why I went for the pescaras in the end...Now I am glad I did, whilst I love the monza look, I've seen too many close kerbings that leave terrible scratches on the surface.
There are also a load of dodgy copies (and better quality copies) out there, you just have to be aware of what you are buying.
Go to a VW dealer....lol...do they EVER actually sell any from there? what are they a corner....£400?
They do come up on forums for sale, you just have to be patient and when they do, don't hesitate else they'll be gone lickety split (or whatever that saying is).