This is ground I've tread before, but I'm hitting it again at another angle.
Put a little tremolo on a clean sound and it begins to sound like it has the power of a distorted sound, without the difficulties of high gain. I set up my Frontman 25R with a moderate amount of reverb — knowing Duane Eddy, I probably should've poured it on — and two takes at "Rebel Rouser". First pass is tremolo off, second is tremolo on.
That's my SX STL50 into a Danelectro Cool Cat Tremolo to a Fender Frontman 25R, recorded on laptop, so you know we're talking audiophile. Still, while it is a simple effect, the resulting sound is much fuller than without, at least to my ears. The good thing about it is that you can play fast enough to hide the effect, then sustain a note and there it is. (Don't thank me, thank Danny Gatton's rhythm guitar video.)
For your edification, this is the lick I was playing.
I suppose I should be fair and show the master doing it....