I don't know much about that topic but wouldn't that be a possibility? I mean an iPhone is just a phone with components in it as any Phone that runs Ubuntu Touch. Wouldn't it be pobbible to replace the Bootloader to get the iPhone to install Ubuntu Touch?
Then you put a sticker on the back and you get a uPhone :D
Not as simple as that.
You would need support in Ubuntu Touch for the hardware in your iOS device. You would also need full access to the iOS device (storage, partitions, bootloader). You also need a hardware infrastructure that allows you to do this. Apple works very hard to make OS changes almost impossible.
