(1) Search for motion capture in the marketplace here. alphauser51 has some really good sets. (2) Are there any other marketplaces where one can purcahse such stuff for use in Poser6? Nope. Sites like the one you're reading, vanishing point, 3d commune, daz etc etc are just figments of someones warped and furtive imagination and don't sell stuff like this :) Of course there! Most of the major sites sell what you desire.

Pinky - you left the lens cap of your mind on again.