I'm a big fan of the Waves plugin Reel ADT. I'll typically just take one channel and bus it into it and turn off center...or bring it down. 
 
On other occasions, I'll just double the take and pan them L/R and slightly move one of the tracks left or right...it's a nice effect. 
 
I also like SoundToys, Microshift. You can spread the upper frequencies and apply a low cut if you want the lower guitar frequencies centered. 
 
Matthew Lane's DrMs is pretty cool too. 

1. make sure you're working with mono guitar tracks.
2. make sure the two rhythm guitar tracks are significantly different-sounding from one another.
3. don't bother with doublers, choruses, mid/side processing or "wideners". Those will not help you achieve the effect you're after. Experiment with such things only after you've already got the tracks where you want them.
 
Once you've got two distinct mono tracks, you will be able to place them anywhere in the panorama you like, whether spread all the way to the edges or in a more realistic audience-view layout. You'll also be able to automate panning so that the rhythm guitars are more centered until the lead guitar comes in, at which time you can push them out to the sides to clear a space for the lead.
 
But all this is do-able only if you start with dissimilar mono tracks.