Does it really need to match the color of the shocks? I think that's one of those things that just won't see very often, and when you do, your mind won't include it in the overall color scheme. The truck already has orange lights/reflectors, red lights, clear/white lights, silver reflector, black tires...that are never considered when looking at colors on a truck.
Another thought about these sort of accent decisions to consider is "avoiding expectations". Matching colors are nice, but if it's blends in with what every other truck looks like, it's not going to draw attention. Even something as simple as having a black license plate, when the standard plate for your state is white, will standout...even on an all black truck.
