It would seem to me that what you gained near the sound hole you would lose in playability for the fretting hand. It makes more sense to me that it is the build of the guitar that would determine flatpicking or fingerpicking value. A dreadnought is going to have more boom and volume than a parlor size guitar, likewise if you are going to be fingerpicking a smaller body guitar makes more sense as it is a little easier to get your arm around (fer us little folks, anyway). I would also think if you were seriously trying to build one or the other that wood type and thickness would come into play - for instance flamenco guitar tops are extremely thin and bright, but they don't last near as long as a thicker top, nor do they have the sustain (which, in flamenco music, is not necessary). I would also think that string choice would be a factor as well.
I'm like Homeless here. I've never gone into a shop and seen guitars divided "flatpick" and "fingerpick." Choose the guitar you like and play it both ways.