Yes, one would probably have to use a medium format CCD camera or a D800E with a very good 28mm lens to get comparable results, but such a combo would be several times heavier and several times as expensive as a DP1M. Of course we all know that medium format systems and professional FF DLSRs offer other benefits that may well justify their price and weight, but if you are looking for an affordable, compact camera with ultra-high-end IQ to shoot outdoors in decent light, the Sigma DPM series is it. I got mine for 599 EUR (incl. VAT) at a brands4friends sale. At that price, the camera is almost impossible to resist if you are looking for maximum IQ. Zeiss would probably charge more for a 19mm APS-C lens w/o the camera.
Of course, the battery life is bizarrely short in this camera (but you know that in advance, because it's clearly noted in every single review, and the camera ships with 2 batteries, anyway), so you need to get a few more backup batteries and maybe a second charger in order to comfortably shoot for an entire day. You also need a large and fast memory card (32 GB or more) to store the huge RAW files the camera produces. I also bought the lens hood and a 49-52mm step-up ring to fit my 52mm Fuji ND filters. Luckily, those accessories are quite affordable, so you don't have to buy third-party knock-offs.