You're not going to find much faster than Michael Angelo. He anchors his picking hand with his pinky between the pickups, so maybe he's a good example for you? His instructional DVDs are pretty good - as long as you want to play like him.

The most useful advice I can probably give is to use a metronome, and move it up 1bpm each day - you probably haven't hit a wall, you just don't notice the progress anymore. If you do that, you should be able to keep your picking clean while gradually increasing the tempo.

On picks - I like the Dunlop 'Big Stubby' ( :o ) picks, but I can play the same with pretty much any pick over 1mm...