You'll probably never find a texture for v3 or any other unimesh female with accurate genitals. If you look at the unimesh template you'll see that the anatomically correct spot to paint genitals is cut into three parts and split up. 1/4th of it is on the left buttock, 1/4th on the right buttock, and the upper 1/2 is in the middle. Then like gwhicks said, it's also an area where the mesh is stretched when moving the legs even a tiny bit, and even if the pose is zeroed, there is texture stretching and warping in that area. A genital prop like arduino's is as good as you're gonna get with a unimesh figure.