I order direct from Germany as much as I can, some of them I've bought 2nd hand from ppl I've met on the forum.
You can look at this place from Germany, a wholesaler for Stahl, Leimbach and various others.
TTM Modelbau
Larger than 14th scale rc can be purchased here for nearly the same price as Stahl/Leimbach constr models.
Vario Earthmovers I recently aquired the John Deere 850 (14th scale), the JD 450 is the 12th scale version with the only difference being the cab/body.
I've been tinkering a bit last nite with the 850, probably some more tonite too.