Bec, were you talking to me? I'll give you a long, droning response regardless.

As far as accessing other application's private data stores, I have not yet looked into that for a non-jailbroken device. It was once on my list, but I hadn't thought about it for a while since yesterday.

There are actually three types of developers for iOS devices. Those that jailbreak, those that contribute to the App Store, and those that develop for personal use. Of course, someone could wear any combination of those hats, but for the time being, I'm only in the last category. It costs me about $100 a year for the "privilege". Without using the App Store regulators, I'm allowed to share my apps with 100 other devices. But what if everyone paid the extra $100 a year? A whole other ecosystem could develop, and would Apple really care? Uh, probably. But I'm guessing a $100 a year (of which Apple would only get $30) is more than the average iPhone or iPod user spends on apps. The iPad is a different story, but most apps don't have recurring costs like the developer subscription fee.

Anyway, I have my irons in many fires, but because of the relatively tight coupling of hardware and software, I like to keep my Apple products closely compatible with the mother ship. I rely on these products, and I want to give Apple the least opportunity to intentionally or unintentionally break them. Did you listen to Steve Jobs' last keynote? He gave his three reasons why apps get rejected from the App Store. One of them was because of people using private APIs. Well, sometimes I like to dip into those private APIs, and it usually is as easy as circumventing an #ifdef. I could go on, but I hope you get the picture.

Why not be very specific about the formats that interest you, then someone could possibly give you a more definitive answer. An interesting note that I've mentioned here before, in iOS 4, Apple has opened up general access to the other processors. If someone was so inclined, porting hardware accelerated versions of video and audio codecs should be easier.