I am making a banana nut cake with cream cheese frosting for a birthday.
What do I use for my decorations and writing? Regular buttercream? I don't think buttercream and cream cheese will be good together?

I would use either the Wilton White Chocolate to fill various molds to use as designs or make the Candy Clay (14 oz bag of candy melts + 1/3 cup light corn syrup). To make the candy clay, you melt the candy melts and then add the corn syrup and stir till it thickens and all of the corn syrup is mixed in. I then lay out two sheets of clear plastic wrap and then pour the candy clay out onto the plastic. Here's where it gets messy. I use paper towels to absorb some of the oil -- using the plastic wrap to lift up the candy clay so that I can keep moving it around and pressing the paper towels into it so they absorb some oil. Once I see that most of the oil is gone, I wrap up the candy clay in the plastic wrap and put into a ziploc bag and store over night. The next day you have to knead it and then use it like you use fondant.

Unless you are going to decorate this cake *to the hilt* the small amount of b'c will not even be noticed. I say go with it.

Thanks!

I'm with kakeladi noon will notice if its only basic writing and deco. We used buttercream for all our decor on creamcheese icing at our bakery no one ever complained!

Candyland Crafts and probably other online stores sell flavored oils. I bought one in cream cheese flavor and added it to my bc to do the decorations on a cream cheese frosted cake.
I agree with the other posts. You probably don't need too, just another option.