I've never heard of a black cat with odd colored eyes. Maybe someone asked that question in the Genitics forum? Might be worth checking out. However I've seen other colored cats with odd eyes, like Turkish Vans, Japanese Bobtails, which aren't white. So I wouldn't say it was impossible, and our dog who is a Black Bicolor.. She's Greyhound/Border Collie cross, has odd eyes(copper & blue) Hedi, that's not true, orange eyed whites are much more common then odd eyed whites, and I'm pretty sure(even google searched) that no problems come with odd eyes, it's actually the blue eye that causes the deafness.
Hope this helps.