Yeah, I write iOS apps professionally, and therefore also have a developer account too; so unfortunately, that's not the barrier. The barrier is the lack of API, which you've stated. I had to reverse-engineer each API and then scrape/parse HTML for values, which was a long and painful process, which I would have to redo quite a bit of that for the iOS version. But, I'm looking into a way to convert the the code I wrote to scrape and parse the values to iOS (maybe cross compile it to C or something...), which would make making the iOS version much more of a palatable undertaking.
I've also been toying with the idea of open sourcing the app--especially since it's free. It could open up the world of possibility quite a lot. So we'll see. :)