I believe the hands/fingers from the Poser 4 female was one of the issues with an "original" figure not long ago, and they got in serious trouble, fast. Folks do examine meshes, and recognize "borrowing." You're always better off studying what's out there, but building and rigging your own from scratch - then all those hours will go toward building your skills. Be sure burn your steps from the beginning to backup CDs, and you'll be covered when someone questions your copyright. If you want to create a modification of an existing figure that folks who own the original can use, you can create an item that points to the original geometry file, or encode a .pcf, etc.