Yes you can make banana ice cream with a blender! Just freeze some bananas for a few hours (or keep them in your freezer, and thaw them for an hour), and blend it up. I make it in a food processor though because my blender doesn't work well at all. I make all kinds of things in the blender/food processor. This morning for breakfast I blended 7 bananas with 6 ounces of blackberries. I love to blend bananas with dates too. Yum!
I make it with my blender too *e-high 5 to arnolds way* i just take my frozen bananas, add a little water, probably about 100ml and blend away. I usually have to keep stopping and poke them down between spins but the outcome is tip top!