Todd Keehn is the sole employee of TK Instruments and I've always been impressed with his guitars. I found out about his guitars from an Australian guitarist who was performing a specific piece of music written by a British composer. It took about 5 years for me to realize Todd lives a little north of Phoenix.

Anyways, he uses carbon fiber rods in his guitar necks and has an option for something called the CARBON FIBER D-TUBE NECK BEAMâ„¢, Here are two links relevant links:
http://www.tkinstruments.com/guitar_bas ... m_shop.htmhttp://geminimusical.com/carbon-fiber-d ... k-beam.aspI'm not suggesting you buy a custom guitar, but luthiers tend to build guitars that address problems caused by the local environment/weather. Knowledge of their solutions can be very useful especially if you dealing with a company like Warmoth. I'm not sure Epiphone really cares what the weather does to their guitars in Tucson, AZ.
I have a 7 string classical guitar built by Jeremy Cooper who is a local luthier. He uses carbon fiber rods in his classical guitar necks for stability. Depending on the guitar, he will use two thinner rods or one thick rod. My guitar was the first (and only) 7 string he has built so there were some "unknowns" he had to deal with. He basically decided to use two of the thick carbon fiber rods in the neck of my guitar "just to be safe." I have nothing but good things to say about the neck on that guitar and I wish all my electric guitars had two carbon fiber rods in their necks. Which brings me back to the CARBON FIBER D-TUBE NECK BEAMâ„¢, it must work if Todd is willing to build electric guitars without truss rods in Arizona. It would be to much of a risk otherwise. Thats just my opinion though.