Ok, now I am more confounded than before! All these ideas sound fantastic and I want to try them all!
I am leaning towards the banana split idea b/c I think I could do something interesting with that which will allow me to attempt some different techniques.
I have one set of cakes (went into a pre decorating baking frenzy last weekend and have 6" rounds out the wazoo) that is a mix of chocolate and banana, so maybe I'll do the "split" for that one and a cream cheese for the regular banana... decisions, decisions.
Thanks everyone for the great ideas.