Black & blue!
well the world is very politically sensitive about colors so we just talk about problems in how much white it's got in it, regardless of the color..
things are black and white ONLY in our heads - the universe itself is all grey - ever shifting, ever changing, shades of gray
other colours, in terms of your analogy, have no real meaning - if we introduce them we lose the meaning about polemics at the heart of the original saying, which is that reality usually lives between two extremes, and not at one end or the other
red, green, yellow and ofcourse blue
well, red problems are communist ones, pink problems are girls problems, rainbow problems are the gay communities problems, yellow problems are chinese/asian problems, etc etc etc
seeing red. got the blues. green with envy. yellow streak