I've got killer, huge rhythm tracks... now about the solo tone...

[PhiloBeddoe]

All IMO and FWIW, I think you might try dumping at least few of those rhythm tracks. At some point it becomes distracting having so many. The wall of guitars is often better suited for pads like slow power chords. Faster moving riffage will become clearer and more in your face if there are fewer. You lose the attack when there are lots of guitars.

This will also leave more room for the solo. As for other solo ideas, try something wacky. Different guitars, different amps, different microphones, pedals like tube screamer or wah left in one position. Focus it and make it jump out.

Or not.