The quality from the Merrill series of Sigma DP cameras is outstanding. Unbeatable and unbelievable for the size/weight.
These are very limited cameras in some ways, but perfect for a very deliberate style suitable for landscapes. I've had excellent experience using all three in the outback, handheld as well as on a tripod (I opt for a Tamrac Zipshot).
Here is a stitched photo from a recent backpacking trip in Auvergne, France:
This panorama was stitched from 9 photos taken with the DP3M. It's been reduced in size so much, posterization is inevitable, but at 880MB for the whole whopper, the color and detail are breathtaking.
Weight of the camera is about 400gr, but you'd better take a quiver of batteries!