Thanks for the info. I think that's essentially the same technique. I pretty much do the same thing, except I either transcribe and use a click, or if the phrasing is weird I use an audio editor and time-stretch one bar at a time until I can play at the right tempo.
Looks like the 'play slow and build from there' approach is the only one. It does work, but i'm still wondering if there's more to it. Economy of motion is definitely key.
Its a mental skill. You can play fast but to what end if you don't know what you are playing or where to go? Speed is a combo of harmonic knowledge and solid technique. The worst thing ever is a guy just playing fast for no reason.
I would suggest learning the major scale (you know it already I am sure, bare with me) so you can use it all over the neck.
For example I can play a Gmin9 and solo all over the upper frets with that by combining it with Bb major since they are same thing. So now I am have total coverage of the 12f fret to the 20th and can hit different licks without hesitation. You need to be able to hear all the patterns and know the notes you are playing. That in itself will make you a faster player.