Did you know that by burying a paving slab under a fruit tree, you stop the tap root from growing too deep and effectively create a dwarf fruit tree? The Victorians (the era, not the state!) used this technique in their kitchen gardens.
Instead of buying grafted fruit trees why not grow a few fruit trees from seed and try this technique.
If the fruit turns out to be no good then pollard it and graft something that you know has good fruit.
If you live in the Blue Mountains then you can probably miss out the paving slab bit and find somewhere that only has 30-40cm of top soil (like my front garden)!