Confusingly, there have been 4 fairly different versions of Epic. Here are the stats for Eldar Knights from WD126. They are from 1st edition Space Marine (as epic was called back then), and have the original names for the weaponry:
EldarKnightsWD126.jpgRules for 2nd edition Epic were printed in Citadel Journal 1, which I don't have access to, but are bound to be similar to 1st Ed. Epic 40,000 is the 3rd edition of Epic, and as such has no rules for Eldar Knights that I'm aware of
. However, the most recent 4th edition (Epic: Armageddon) has some rules on the last page of its Swordwind supplement (downloadable from GWs website). The stats here basically compare the knights to pre-existing units:
EldarKnightsSW4.jpgGlad that people still play this great game. Hope that helps!