Instead of shred, I like to listen to stuff like this:
http://www.youtube.com/watch?v=HVrRTVKVr6Q
Which is the same idea, super technical playing, a million notes, but I can actually stomach this, and not just because the Captain wrote it. I don't know what you'd label that guitar composition under, and there's no sweep- or tremolo-picking or whatever, but it's just as technically challenging, if not more so, than a lot of "shred" stuff.