Here are a couple of Scouts from my Gorgon Knights chapter. Rather than go with the usual gold, I decided to make it a much darker scheme than usual, while simultaneously making a subtle reference to the Iron Hands (their parent chapter). They are after all Scouts, they infiltrate and tend to rely on stealth. Wearing bright colors doesn't help that at all. A subtle detail that I'll be incorporating is (with the exception of the Sergeants) is the fact that the Scouts don't bear the chapter emblem, a right that they earn when they become full battle-brothers. The most noticeable thing is the use of Pig Irons' Heavy Infantry heads. Even though they're space marines, they still wear helmets into battle. Doing anything else mere combat stupidity.
The paint scheme was heavily inspired from the Halo series of video games - mainly on the Orbital Drop Shock Troopers (the best of non-augmented human soldiers). I have a hard time painting with darker pallets. I find that trying to stick to it creates a rather boring model. Fortunately, it allows me to play with metallic paints much more than I'm usually able to and try to simulate a True Metallic look. The helmet visors were definitely a nice contrast to the rest of the model.
As usual, C&C welcome.