It looks like My Fav Guitars is closing soon per Jon's recent retirement announcement.
I also recommend Acoustic Vibes. I bought a Collings mandolin there a few years ago.
Also, there is a place north of Scottsdale called Cave Creek Guitars. Not much of a website, but that last time I was there they had Collings guitars and some high end Fender electrics. Some used stuff.
https://www.cavecreekguitar.com/