I've considered this. Multi-touch would be great for this. Pinch horizontally to shrink the selection, anti-pinch (I've never really though about what that motion of moving your fingers apart would be called) to expand the selection. Pinch vertically to be able to drag it around and drop it where you want.

I can't wait for a 28" touchscreen at my desk with some software to make the touch interface and excel, CSS and other random statistics programs work together a little better. It will genuinely make work easier, and make me more productive.