It might, but at the expense of making the device bigger or the screen smaller, both pretty undesirable in my view.
There's no perfect solution to that general problem as far as I can see. There has to be a compromise. Apple went big screen while (most) others have gone small screen or slider/flip. The advantages to a big screen in a small device are obvious, but I'm guessing that a lot of the success of the iPhone will hinge on how people get on without a lot of the mechanical controls they're used to. In the MacWorld keynote Jobs made play of how much more flexible the interface is when freed from buttons. That's true of course. A device with a mechanical QWERTY, big screen, phone buttons, a bunch of PIM app buttons, and a click wheel doesn't sound too great to me