Just a little "survey", but for you, how important is being able to contact manufacturers due to warranty issues, upgrade questions or just to ask a simple question about your bike? Would that convenience to reach someone influence your final decision when buying a folder, or expensive components/quality of the bike (even if the manufacturer doesn't care about folders where you are located) is way more important?
So far, I believe Downtube as well as Dahon owners are pretty well served as far as reaching them. As Denis said in another thread, "the top 4 (C'dale, Giant, Specialized, Trek) are too busy making money elsewhere."
If they only knew...the POWER...of the Folder (heavy breathing under mask...)