I know there are many great meshes/skins out there of Diana. All of them that I know of have the golden lasso as decoration only.
There is a mesh out there for Wondergirl that has WW skins for it, and she actually uses the lasso.
Fusion did a series of meshes, WonderWoman, Donna Troy Wondergirl, and CSA's Superwoman, all of them have ranged animations with the lasso and really cool idle animations, swinging the lasso around, i think they are available in his yahoo groups.
Found her and she is nice! The mesh is dark however even after converting it. Any idea how to lighten it up?