Are you guys familiar with the Magic: The Gathering colour wheel? It actually acts like a rather interesting morality system.
Generally a colour opposes the two colours opposite it (for example, Green, the primary colour I actually play in my decks, opposes Black and Blue), but there can be combinations of opposing colours in a single individual. A few examples under this system:
Andreus Ixiris: Red/Blue. Andreus is a creature of odd contradictions and extremes, as befits an opposing colour combination. He's often torn between the logical and emotional reactions to a situation.
Anslo: Pure Red. Impulsive, unpredictable and deeply opinionated, Anslo is an excellent example of this monocolour.
Saede Riordan: Pure Blue. I wanted to say Blue/Black, but Saede isn't amoral or self-focused enough to be Black. At least from what she says about herself, she seems to be pretty focused on the application of technology to the advancement of humankind, which is an incredibly Blue outlook.
Silas Vitalia: Pure Black. She wants what's best for her, and no-one else, and she's entirely honest about it. She doesn't lie habitually or compulsively - she only lies when it's useful. She'll be charmingly polite or bitingly malicious depending on what best suits her purposes. I struggle to think of a character who's a better example of this colour.
Rodj Blake: Pure White. Values order, conformity and rule of law over all other concerns.
Stitcher: White/Blue. A sedate but powerful combination that merges White's desire for stability and peace with Blue's penchant for progress and application of intellect. Many Caldari are White/Blue - it's actually a defining feature of their society.
Pieter Tuulinen: White/Blue/Red. Like all colour combinations with more than two components, Pieter is complex. Just like Stitcher he merges the standard White adherence to law and heirarchy with the Blue tendency towards progress and innovation, but from what I've seen of the character it's also tinged with a fair bit of Red's powerful emotion and tendency towards spontaneous action.
Sansha Kuvakei: White/Black. Another opposing colour combination, and another creature of extremes. Sansha Kuvakei is quite evidently deeply self-obsessed, since he's built an almost religious following around his beliefs, a following which really only works to his benefit. At the same time, at least part of him genuinely seems to believe that what he's doing is good for humanity, and that part, in its own twisted way, seems to want to share Sansha's "gifts" with everyone because it genuinely believes they'll help.
Only problem with this is that I'm having a hard time finding any good examples of Green characters.