Currently, models from Ninja Gaiden Sigma and Sigma 2 are not extractable. You'll have to keep waiting for your Rachel fix, folks. Sorry!
Also, models from Heavy Rain are also non-extractable currently.
Oh, and one more thing for newcomers: Make sure to also browse through DeviantArt.com, as there are quite a few models posted there by members who are not part of this forum. The model you're looking for might be there, waiting for you to download!