Part of the resume read:

Underground Development. (Activision), Redwood City, CA. 2010
Concept Artist.
Character design, Environment design, Props design, UI design, Story boards, and Text artist for Guitar Hero Van Halen, Band Hero 3, Guitar Hero 7

We knew that Underground created GH: Van Halen, but it appears that preliminary concept work had been done on Guitar Hero 7 and Band Hero 3, neither of which have been announced.

Neversoft is currently working on Guitar Hero 6 with a release planned for the second half of 2010. Activision has confirmed Band Hero 2, but later announced plans in February to cut back on music game releases, insinuating that only Guitar Hero and DJ Hero would continue to get new entries. Later, in May, the company highlighted Band Hero's performance and is most likely still developing a sequel.

With Underground reportedly shuttered, it is quite possible that the concept work done by Nigel Li and others will never manifest itself in a released product. Expect Guitar Hero 6 and Band Hero 2, should it still exist, to be revealed at E3 2010.