I'm wondering if you at least have a basic understanding of how manipulating 3d geometry works. Ok, you can scan a real looking girl, but making her move(especially if she's realistic) is incredibly difficult. I've been doing it for years, and can tell you it's not easy.
Remember, this has to work in realtime, so scanned model(high poly) with deformable joints is going to take artists at the level of ILM or Digital Domain, and the end user will need superior hardware to run it.
__________________
|