Banana smoothie with just ban and ice?

Yes add some milk as it is blending if it's not flavored as you would like add a touch of vanilla

As long as you add some milk, you're OK. There has to be a liquid portion in a smoothie. It won't taste like much other than banana, but it will still be a smoothie. Actually, bananas are a great thickener for ANY sort of fruit smoothie.

Any other type of fruit. Also something sweet sugar or ice cream. Fruit jelly might work. Bananas do not have a lot of flavor and are not that sweet so maybe some chocolate in the blender like a candy bar might help.

I don't see why not - I just made one with only bananas, milk and a couple of cubes of ice. Only thing is that without yoghurt, the smoothie isn't going to be as smooth - it's a lot more runny. But still delicious!

the smoothie will taste nice with either lowfat ricotta cheese (sounds weird but tastes creamy) or yogurt any flavor. If you aren't weight concious than vanilla ice cream. Other fruit might be nice too but just banana and ice will be watery.

That sounds like it will work.