Some recommended reading:
The most recent issue of the Journal of Medieval and Early Modern Studies is devoted to "Theory and the Study of Premodernity." Sarah Kay has a good piece on flaying and textuality, Paul Strohm provides a typically rich read of the death of Richard Duke of York in 1461, and so on.
I found Daniel Boyarin's JMEMS essay "Apartheid Comparative Religion in the Second Century: Some Theory and a Case Study" especially illuminating -- and useful. Boyarin maps how the line separating Jews and Christians came to be drawn, how the differences (and separations) between Christian and Jew had to be produced, and how in the process the intractable impurities that actually marked both these identities were denied.
Perhaps hybridity is just a personal obsession, but I'm in the process of blurbing an excellent forthcoming book by Kofi O. S. Campbell on the subject (De-Centering the Middle Passage: from Pre- to Postcolonialism on the Black Atlantic, coming out at Palgrave Macmillan). Added to good postcolonial medieval studies on the topic by scholars like Patricia Ingham and Michelle Warren, Campbell's book and Boyarin's essay suggest to me that postcolonial hybridity is a topic medievalists will be pondering fruitfully for some time.