Wouldn't it be easier to just wrap apps for Android? Isn't that linux based already? I guess I don't see the point of buying an expensive iPhone and replacing the OS as that software that originally comes with it is why the iPhone is so great.
Lets put it this way. If you had Linux on the iPhone. You could:
1. Run almost any linux software (probably including all the nice openGL desktops too)
2. Play any format of video or audio that exists.
3. Encrypt your personal data.
4. Probably use wine and run StarCraft, Colin McRae... well basically any game that wine supports and the graphics hardware on the iPhone could handle.
5. Have a full featured desktop environment
6. Basically do anything you wanted to.
If you can already do everything you wanted to, then you dont want much