I don't know if you have seen the character maker application that I am working on, but I use TextureMax for the character model texture manipulation. In fact, that is how TextureMax was born. I needed something to handle the Texture manipulation for the character maker. As I was working on it, I thought other people would find it useful too.
I must admit, the TextureMax editor isn't the best work that I have ever done, but it does do the job. Once you are finished creating the TextureMax file, the dll handles it really well. It is fast and the results are good.