I've searched and toyed with this for quite some time. I have a penguin who's body is egg shaped and I'm trying to do the UV and texture for it. If I use projection from view then it comes out nearly OK except for a few areas (see image). The problem is that it seems no matter how I change the UV's vertices I can't fix the offending areas. I'm hoping someone can help. Thanks!
Try to reproject your texture upon a catmull-clark subdivided version of the mesh with the subdivide UVs option disabled.
This way you should be able to have more faces (and so a higher projecting accuracy), while maintaining the same UV islands.
In my testfile this process was able to mitigate the effect of the distortion.
Once reprojected the texture, you can obiuvsly delete the modifier and keep your vertex count untouched.