hmmm. i suppose just knowing your modes front and back is good in any case, because fusion incorporates modal ideas frequently. i've actually been writing pages and pages of legato and alt-picking exercises that go up and down the neck on each mode, and from writing the exercises i've gotten better at picking out my modes while soloing. if nothing else, know all seven modes so you don't get stuck in a certain position on the neck while improvising, soloing, or whatever. learn them in 3-note-per-string patterns because those are obviously most effective for playing fast and if you learn them all the same way (3 notes per string) you can sync your modal runs up seamlessly.


i know the dorian mode is overused in rock music, it's great for a mix of medal madness and melodic clarity. try playing a dorian scale with the b5 like you would use in the blues scale. it creates some cool symmetrical patterns for you to wank around on. take note:



-------------5-7-8-----------------
-------5-7-8-----------------------------
-5-7-8----------------------------------------
---------------------------------------------
---------------------------------------------
--------------------------------------------

when you add the b5, the top three strings are identical in fingering, which are great for soloing and moving horizontally along the neck. the b5 also sets up for a nice raised-seventh sound in the phrygian mode, located right next to the dorian riff.


----------------7-8-10-----
--------7-8-10------------
-8-9-11----------------
------------------
--------------------
--------------------


i know this isn't very deep and you where probably looking to find a sacred book of scales for fusion or something, but most of it is just using your scale positions effectively. there are some cool exotic scales you can tool around with, like the japanese pentatonic scale and stuff like that.