Last time we spoke to BenQ they indicated they would be concentrating (for their branded phones) on developing Windows Mobile PDAPhones, and that rather than releasing the P31 themselves they would be looking for an ODM partner. Clearly they have found this partner in Nokia (BenQ also provided Nokia with the 6260), although it is not clear whether their agreement preclude similar ODM deals with other manufactuers or operators.
The N6708 is the first Nokia UIQ handset, but it is does not necessairly mean a major strategic change for Nokia. While it is possible Nokia is considering UIQ for further pen based phones, given this is an ODM phone it may well be a one off, that seeks to serve a specific market. Series 60 3rd Edition provides support for alternatve input methods (including touch screen), and it is more likely that this would be used in future Nokia models.