Its hard to speak of epistemology without mentioning Foucault. He's a great philosopher of the history of knowledge and its preconditions. I have not read Feyerabend (yet) though. But if he's going deep into the history of knowledge, there will be at least some associative closeness if not one in methodology. Foucault, studied under Georges Caguilhem who was an influential philosopher of sience. Another student of his is Gilbert Simondon, a philospoher of technology who was writing on the process of the individuation of machines. I say this because I sometimes get the impression that some people, especially those educated in the US, have a quite distorted impression of the so called continental tradition. Also if one was to speak of a certain group of philosophers in France after May 68 like Foucault, Derrida, Deleuze (who are actually rather different thinkers), they are commonly reffered to as post-structuralists, not post-modernists. Haven't heared the latter term to often in philosophical debates as in use for people. Of the top of my head I can' t really think of a person that could function as representative of postmodernism as a coherent school of thought, besides maybe Francis Fukuyama. Maybe thats different in US discourse. The term post-modernists always sounds a bit funny to me, like the "Neomarxists" that haunt the plot of Southland Tales.