It appears that Microsoft has unintentionally outed the next generation of its range of Surface tablets before the first generation has even been released.
At least a dozen job listings from the California giant's careers page (via TechRadar) appear to confirm that the company is working on the product. A listing for a Senior Software Development Engineer states that the company is "currently building the next generation and Surface needs you!"
There's a possibility that this is just a language error. Microsoft could be referring to its upcoming Surface tablets as "the next gen", but this seems unlikely - some of the job listings were posted as late as mid-June.
Some of the listings state that responsibilities will include "system design and system bring up/enablement".
Considering the Microsoft Surface tablet's final hardware design has been confirmed, it would suggest that this future employee would be designing the next iteration of hardware.