Production of RIM's PlayBook tablet PCs at Quanta's plant in Taiwan have reached an economic scale of 150,000-200,000 a month with shipments to be ready as early as February, according to sources at upstream component suppliers.

RIM has required that all PlayBook tablets be built in Taiwan to avoid of being copied by white-box makers in China, while also protecting its security specifications, the sources added.

Quanta declined to comment on orders for individual clients, but stated that it still maintains sufficient capacity in Taiwan to meet client needs, while the majority of its production lines are in China.