let me know how it turns out, I saw an ice cream maker today at the market, hmmmm....we just do it this way b/c we only have a blender, but I have managed a lot of fruit sorbets. I like this b/c it doesn't need sweetner. The kids just think it's ice cream and they think I'm great for letting them eat as much as they want!
Maybe you could add cocoa to make it chocolate-walnut-banana, I am thinking to try it next time