This is more limiting than a surface breakdown or early success book, but I thought I'd offer it. As a straight up pedigree resource that you could certainly apply should you wish to, Avalyn Hunter's book American Classic Pedigrees: 1914-2002 is good. It covers the Derby, Preakness, Belmont, KY Oaks, and Coaching Club American Oaks. I hate to be all "there's pictures!" but there are some in there. It's not like she specifically wrote it to help you handicap, but if you're thinking about stamina influences and soundness at the very least, there are worse ways to go about it. She's researched her eyeballs out on this one, and it's well written, not dry. Lots of context. Obviously there's nothing about Rags to Riches or Rachel Alexandra.
Here it is for free on Google books:
http://bit.ly/c28Fnn
If you want to buy it:
http://www.amazon.com/American-Class.../dp/1581500955 It's not cheap, but I got one for $50 used. It's doable to find it for that, and definitely worth it.