It was hard enough getting it to work on Raspberry PI, which has a completely open OS. iOS is completely closed, and porting is not possible. The reasons boxmein said is true too apart from the processor on newer devices only, iPhone 4S and iPad 3G in theory have enough cpu power to run TPT.
I thought iOS processor is faster than computer processors
In theory, if it can run on a raspberry pi, it should run slightly better on iOS, the thing is porting all of this code to Cocoa would be very time consuming. Unless someone will port it to Cocoa, then it will become a maybe.
Raspberry Pi uses single core 700 MHz 256 MB RAM.
iPhone 4S uses dual core 800 MHz 512 MB RAM
iPad 3rd Gen uses dual core 800 MHz 1024 MB RAM
This kind of App would run more than nicely on an iPad, (for screen res anyways) but on an iPhone or iPod Touch is not the croud that the app would be for.