Challenge looked fun and I've done a slight NES Mega Man revamp before so I thought I'd have a go. Seems I'm still in in the 'Robo-zone' of my current game project so this happened...
Preview is RoboCop colours. Main file is Mega Man colours. Best viewed zoomed in and blocky as intended (looks cruddy at your normal high resolution). NES palette and limits. Same sort of thing as the original Mega Man sprite with the overlayed skin tone sprite on the face. Unlike my other sprites for this challenge, this one is built to the size and proportions of the original Mega Man sprite.
Hm, now that I sit back and look at it, the idea just seems so... right... Y'know?
Other alternate palettes (like Mega Man does when changing weapons) can be seen at carnivius.deviantart.com/art/MegaRoboManCop-450730437
Updated: Now comes without helmet too. :P