This is the local mushing group (you can find Balto Team Dogs on facebook) from south central PA and northern MD. Someone in the group knew this lady and mentioned it... yep, 6 Jack Russels, skijoring ("she had to ski like mad to keep up")... presumably typical x-backs in pairs on a central gangline, nobody here does a fan hitch because most of the trails are narrow wooded trails or rail trails, no room for fans.
My Schipperke was about that size, 16 pounds, and maniacal, even though he was pretty old when he started (10). He pulled like a crazy Sibe, even when we were standing still... of course we ran a bit slower to keep him comfortable (a nice brisk trot) and when he tired, he rode in the back pack on the sled or rig...