Memnoch
Lt. Vulture
Light up eyes on C3P0 are a must. And I think the HT Iron Man is a bad comparison - closer would be the Battle Damaged T800 and Endoskeleton, both of which featured light up eyes with a small battery in the base of the neck, and most of the electronics limited to the head. Easy peasy and shouldn't really add much to the final price.
This info about the T800 Endo has me intrigued.. can you describe how the battery is at the base of the neck? I really don't wanna see any visible batter compartments on the final figure if it can be avoided.