I hesitated to show this stitched image due to things being cockeyed; I shot it in a hurry using a tripod, but without doing the proper leveling or using the proper multi-shot stitching or panoramic hardware like that from Really Right Stuff.
The image below is 66 megapixels (9170 X 7300) after stitching and cropping the stitched result, stitched from 10 frames (probably I could have done it with fewer frames).
The actual pixels crop below represents the sharpness of the entire image— I’m not seeing any weak areas, or stitching seams. The point being that with a point and shoot camera on a tripod with proper hardware and some care for rotating about the lens entrance pupil, one can make images rivalling (or exceeding) detail of the highest resolution medium format cameras available today. Weak spot: the dynamic range of the DP Merrill sensor has its limits as the blown-out sky shows (I could have brought the exposure down to save the very bright sky, but opted not to).
The best camera for high-res stitching is the Sigma DP3 Merrill with its 75mm (equiv) lens. Shoot it at f/5.6 preferably, or f/8 if more DoF is needed.
The best part? The autofocus nails the focus spot-on with scenes like this; just press the button to autofocus, switch to manual for all the frames, shoot.