This can be such a PITA. Try soaking it with some PB Blaster overnight and go at it again the next day with a hammer. I have a feeling, in your case, that the bolt is bent right in the center of the shock. It'll be hard to get rid of the bolt without using force.
As a last result, take a Sawzall with a very small blade and cut the bolt on both sides, between the shock mount on the frame and the shock itself. Once the shock comes free, you can set it in a vise and pound whatever is left of the bolt out of the shock eye. You might be able to drill out the bolt, too, but I don't know if you can get a good shot at it with the drill. The frame may get in the way.
Good luck with it all!