Green
Baldrick made a nugget of the purest green, IIRC.
Also, the stealth implications are more for aircraft and ships than for people. British camouflage has very little black, mainly greens and browns (for temperate climes at least). If the aircraft absorbs all the radiation and doesn't reflect any back, there's no way of picking it up on radar, much like the current stealth technology, where a big evil aircraft shows up about the size of a large bird.