Ok- forget the rotary dial.

How about a standard 12-button dialing pad that is at the *top* of the screen?
I don't understand the cellphone obsession with the low-input/high-output layout. Why not put the input where your thumb is?

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[1-888-555-1212]

Seems like this would put the majority of the unit into your palm.

(Bear in mind that I do not own an iPhone and I'm posting purely for some mental diversion. I *did* try to search the app store a little, but it wasn't a pleasant experience, so I quit.)