You are mistaken.

Nearly all via netbooks use via reference platform for Tablet PC. None of the manufacturers is doing any design either. This includes the HP2133 which is a classic example for a via tablet reference design.

They all are killed by the ultimate bane of all Via motherboards - the S3 derived video. Let's face it - its performance is not on par with the rather weak Intel onboard videos even on the few MBs where it uses dedicated memory. Example - the average CPU load on a Via C7M clocked at 1GHz playing Planet Earth to 1280x1024 screen is around 70%+. The system barely copes. Put an nvidia in and voila - loadaverage is down to 30%.

It is the weak video subsystem that stops Via from doing any inroads in this area. They are trying to compensate by adding bells and whistles like mpeg accel and so on, but all of these are rather pointless if the underlying performance is so low that the consumer can notice it straight away.