The Bercomac website has a dealer locator. There is also a company called originalcab that has a few options and another called universal tractor cab that will ship directly to you. The Berco was the most affordable that I found.
Looks good. I want to buy my father-in-law a soft cab for his Deere and I'm looking at the Bercomac options. What size berco cab did you install? The 34" or 40" wide option. Are you still happy with it?