Actually, a 17" MacBook Pro (which has a good GPU) connected via DVI to the LCD "grade" monitor () would probably be plenty enough for on-set and even in-house color grading (ProRes 422 is specifically designed for this kind of stuff). And with an external control interface it would probably not be very far from an ideal "movable grade" studio (previously unheard of).
Remember that Final Touch (which Color is based on) paired with a control-surface had gotten very nice reviews from colorists used to DaVinci systems. The downside was the amount of bugs and the somewhat poor integration with Final Cut Pro. Some found that UI a bit weird as well (doesn't look like Apple has changed much there yet, perhaps Color 2 at next NAB).
