The only waymarked MTB trail on Cannock Chase is Follow the Dog, at least until Phase 2 opens at Easter. The other waymarked trail are the Leisure trails and the DH courses at Stile Cop.
Mammoth Cycles website just links you to our trail map (without acknowledging our existence) rather than giving details of any other trails.
I guess you could get to Sherwood in an hour but really can't comment on the quality of the trails since the money was spent on them last year.
Other than that as Scruff says it's probably Lllllllandingdong.
Chase Trails were the firs to create waymarked trails in Staffordshire (and still are) with no other site following suit. I guess Sherwood is the only other 'nearby' site that has the kind of set up that can accommodate this kind of project?
Stu
http://www.chasetrails.co.uk