Here are a few other places to check things out.

Author of the book, boa expert and friend of Gus Rentfro
http://www.cuttingedgeherp.com

Great quality animals with some nice locality stuff.
https://www.facebook.com/BoaConstrictorDesignerboa/

Locality oriented and has Rentfro (Rio Bravo) stock.
http://www.tcreptile.com/page1.php

Great guy! One of the nicest people in the boa bizz.
http://www.mccarthyboas.com/home.html

Where I bought my boa.
https://www.facebook.com/legacyreptileslocalityboas