Actually, the only black that held up were keyboards with a case made of Bakelite, which was, and still is, the most durable form of plastic available. The color was not a coating or paint, but instead it was impregnated into the plastic, thus it was not susceptible to wear. It was available in various colors, including silver, but if I recall correctly it was about three times as expensive as other forms of plastic, and it would not extrude nearly as well because of its hardness.

I've had lots of black keyboards, they got hot as Hell when you were doing an outdoor job, and they didn't look any more professional than a silver board. For me, silver works just fine. For those that must have a black keyboard, there's always Krylon. It comes in gloss, flat, crinkle, and textured.

Good Luck,

Gary