This probably doesn't help, but I remember reading that you can change the wireframe colour by selecting the object and going to display>wireframe color. I am at work, so I can't check, but I am wondering if you could do this with certain edges. Or if not, maybe you could develop your model to a certain stage and then duplicate it, change the wireframe color on the duplicate, make modifications and then somehow overlay the new one over the old to see the changes?