Paragon Wiki has pretty good ones - female, male, and the unique Cortex. Chaos Leather top and bottom with Sinister gloves and boots (non-plated version) is a good start for a hero trying to replicate one - real Eidolons have unique masks and chest color patterns (the white V shape) but there's probably something similar that PCs can use.
Hey, does anyone have any good quality reference pics of the various Eidolons? I've got an idea for a character, but need to know how close to the Eidolon look you can get with the costume creator.
Thanks,
--Dave