What company, that designed tablets that use Microsoft(R) Windows Mobile, is based in Taiwan?
P535:  At first, the Asus P535 ran with Microsoft(R) Window Mobile 5.0. Asus: AsusTek Computer Inc. (stylised as ASUSTeK or "Λ"SUS) is a Taiwanese multinational computer and phone hardware and electronics company headquartered in Beitou District, Taipei, Taiwan.
AsusTek Computer Inc.