I suggest hunting for and buying the really ripe bananas and freezing them. Here in Perth the markets have them sometimes. I always go on the last few hours of the weekend market.
I'm really struggling with out bananas at the moment too. I'm eating a lot of watermelon instead but good watermelon can be hard to come by and end up expensive when you're eating a lot of it. Plus bananas are so easy to throw in my bag and head out for the day - no mess, no spoons. I will try custard apples tho, haven't given them a go yet. I didn't realise they were high calorie, thanks for the that!
This is average organic price in Adelaide. We are getting most of our cals from California: organic dates. We could grow so much fruit here in Australia but the fruit phobia is preventing even a lot of organic farmers from growing it. My housemate says that most of his customers refused to buy sweet fruits cos they feel 'guilty' eating it! lol!
The solution is to eat more and that will create the $ so people plant more. Demand creates supply. Not the other way around. ;)