I'd be very interested in a low-cost Do It Yourself poser-slanted mocap system.

Budget of, say, $3000? (always gross up and moshi should make plenty, I'd say.)
Acceptable for  this solution.

Dance moves, both classical, like ballet, and modern or even nightclub, important. Since in ballet the dancers move across the stage, this 'small space' could still be used, but you'd have to get crafty.

When the subject of facial mocap arrises, two benchmarks I'd cite would by

Face Robot, from XSI  ($100,000)
http://www.softimage.com/products/face_robot/default.aspx

StretchMark, by Pendulum
http://www.studiopendulum.com/news_markantony.html
They are trying to do what FaceRobot does, but for lower cost. I don't think this is a released product yet.

other links

Dancing bvh at Turbo Squid:
http://www.turbosquid.com/FullPreview/Index.cfm/ID/187368/Action/FullPreview

Gypsy (mentioned above by DaleB)
http://www.animazoo.com/products/index.htm

Note: for anyone wanting to go very low cost, and also learn a lot about body movement, check out the idea of rotoscope; PhilC has a Poser-based rotoscope enabling system in the marketplace.