Came across this link in my random net browsing. Full text of a reasonable selection of older flight sim books. Anything tech specific will very likely be outdated, but I imagine that most of the general simulation and flight related info would still be fully relevant. Not directly cockpit building related, but since most of the people here are interested in making it "as real as it gets" I figured these books would be interesting.

http://www.flightsimbooks.com/