Cherubba, I've done ALL those things and tried beet juice as well. Trust me, do what LPBeier suggests, its the only way to get a truly PINK cake that the birthday girl will enjoy. I've done one every year for about 13 years now. And whatever you do, DON'T try to use your own white cake recipe. It will end up orange not pink!
You're only given a little spark of madness. You mustn't lose it. Robin Williams