I know lots of people ask about the possibility of a 12in MacBook Pro and someone will immediately dismiss it as impossible. Well, for those of you who are so convinced a 12in MacBook Pro is out of the question, what is your reasoning behind it? If it's marketing, did the 12in PowerBook really sell that badly? I seem to see quite a few of them around. Or, is it really physically impossible to fit in a 12in form factor a C2D processor and its chipset with room for USB, FW, dedicated graphics and a SuperDrive? Also, what makes a 10 or 11 in ultramobile laptop out of the question?