This is a fantastic guide Maefly and sorely needed on the Knight forums.
I especially enjoyed your discussion of Overload Saber, as the same question (can I keep it rolling forever?) has been bothering me since I acquired the ability.
As you said, ordinarily OS will only last for 9 seconds (6 at 3 stacks) before dropping. Theoretically that means if you can burn off 3 seconds (2 globals) before applying the third stack, you should be able to restart OS in time to keep the DOT rolling. In reality it may be necessary to burn 3 globals on moves that don't proc OS, due to timing constraints.
Abilities I know don't proc OS: Blade Storm, Force Sweep, Crippling Throw, Force Stasis, Force Kick
Abilities I'm unsure of: Cyclone Slash, Dispatch, Opportune Strike, Pommel Strike
Force Sweep, Blade Storm, and Crippling Throw together are probably sufficient to keep OS rolling indefinitely. Unfortunately trying to use these moves inside the rotation would really screw with focus management, and any DPS gain from rolling x3OS might be offset by using suboptimal abilities as filler. This is a really tricky problem to work out without the benefit of combat logs or training dummies.
In the interim I think its probably best to use your modified rotation as often as possible, preferably getting it to line up with Inspiration usage, and not worry about the rest until more information is available.