In mw2, you used to be able to add ^1,^2,^3,^4,^5,^6,^7,^8,^9,^0
They all made different colours, but the colours on your name where only ever available in lobbies, as black ops has no lobbies you can't have colours in your name.
I also tried to add colours in my classes and it doesnt work, im not sure why.
But if your in a match and say something like this: ^6GG everyone!
It will show up as pink, because thats just one of the different colours.
So to answer your question: Its no longer possible ^_^