Greetings,
I am currently building a similar chart in HTML5 using Javascript, called Spectrum Charts. The format is very similar, but the intitial breakout chart looks more like a split out pie chart, rather than "roots". It is being written in HTML5 using canvases, which is inherent to iphone/ipad ... be cautious about using Flex/Flash in iphone which is only supported by limited apps. Let me know if you are interested and I can send you a limited sample/demo.
As I said, I am already building something like this, so I would charge you less, but still need to know exactly what your requirements are.
Thanks,
Brian