(I'll dip the mouse in hydrochloric acid after this post...)
Doug, already found and sent on stuff on the Fabians and the socdems. A new huge book on the Third Reich by Michael Burleigh, has substantial material on Eugenics.
On Mussolini & Fascist ideology, as a hybrid of left & right see (with his checkered background, kept in mind, as revealed by the website, Institute for the Academic Study Of Racism), "THE FACES OF JANUS Marxism and Fascism in the Twentieth Century http://www.yale.edu/yup/books/078277.htm . Solid piece of work though.
As is, "STERNHELL, Zeev, Neither Right nor Left," Princeton University Press, 1996. (Focus on France but secondary emphasis on Italy.) WOHL, R., 'French Fascism, Right and Left :Reflections on the Sternhell Controversy', Journal of Modern History, vol.63, n°1, March 1991, pp.91-98. http://www.tcd.ie/French/BibliIdeas.html Michael Pugliese