If you are looking for a mastering EQ, I can think of a few options:
-As you said, the GML 8200, or it's mastering version: the 9500. I've used the 8200 a couple of times. Very surgical and precise.
-Massive Passive (Manley). These are quite common in mastering studios, so you're gonna see them often on ebay. I bought one there - it's a warm, colorful eq, with a very nice low end. Not as surgical as the GML.
-Great River MAQ-2NV. I've heard amazing things about this unit.
-Gyratec G14. People in gearslutz praise this one a lot.
There are many stereo parametric eq's intended for mastering in the market, so do your research before getting one. What do you want? A colorful eq? A warm one? Precision?