Hi,
I hated my 85mm 1.8, too much purple fringing for me, I sold it and the person I sold it too sold it fairly soon after that too, so I suspect he felt the same.
I then used a canon 100mm F2.8 Macro for portrait stuff after that and it absolutely hammered the 85mm for sharpness and colour, although slower AF it was far superior image wise, I always think the cheaper Canon lens' have a particular colour hue to them and isn't nearly as good as their more expensive and L lens'
Having re-read you post, I would have thought selling the 70-200 F4 and the 50mm F1.4 to buy a Canon 70-200 F2.8 would be the obvious move for you seeing that you already have the 17-50, no?
Mike.