Several books now online may be of interest to you:
Carl Watner's excellent collection of antipolitical essays by various authors, "I Must Speak Out: The Best of The Voluntaryist 1982-1999" (San Francisco: Fox & Wilkes, 1999. 499 pp.) is now available. This collection contains some of the finest essays from the nonpolitical (or social) libertarian standpoint available. For those who are only familiar with the political libertarian thinking will find many of these essays an eye-opener.
John A. Pugsley's The Alpha Strategy (Common Sense Press, 1980. 194 pp.) is also available at his Bio-Rational Institute (which I recommend). This was the work that brought John Pugsley on the NYT best-seller list for 9 weeks.
Richard D. Fuerle has two books online: The Pure Logic of Choice (Grand Island NY: Spooner Press, 1986) and Natural Rights: A New Theory (2003). The first work I read when it was published and was quite impressed with it. It still holds up quite well as an independent work on Austrian economic theory and freedom. The second work I've only cursorily read and find his theory of rights coherent and his elaborations worth reading more carefully.
Just a thought.