Author George Cearley, Jr., was a big fan of Braniff. His book on the Boeing 707 features quite a few pictures and photos of early Braniff 707-227s, with a 720-027 or two thrown in, all in the pre-Girard markings. He also wrote a book on Braniff. Unfortunately, people are asking obscene prices for these rare books, but keep looking - you might get lucky and find one at a reasonable price.
An interesting little tidbit - the L-149 Constellation preserved at Santa Cruz, Bolivia, is none other than former Braniff's N2520B, the subject of Corgi's 1:144 scale model, making that item a highly worthwhile and interesting collectible for any Braniff fan. I have it - it's a very nice model. They appear every once in a while on Evil Bay, and if you can wait, you should be able to pick one up at a reasonable price.
The aeroplane has unveiled for us the true face of the earth. -Antoine de Saint-Exupery