Vizio is an American company started by a Taiwanese native. They get 85%+ of their products from AmTran (
http://www.amtran.com.tw/), a Taiwanese company who also owns about 20-25% of Vizio.
As far as I know, AmTran does not build their own LCD panels. I believe Samsung, Sharp, Phillips, and Sony have pretty much a stranglehold on that operation in one capacity or another.
Effectively what these companies (Vizio, Olevia, Westinghouse) do is buy the overstock or b-stock equipment from everyone else and slap their own cases on the stuff.