I always enjoy reading camera and lens evaluations by Petteri Sulonen and have been waiting for this one since he first mentioned an interest in the DP1. Petteri has now posted his impressions, "A Diamond In The Rough: Sigma DP1". Having read every piece I could find online about the DP1, in English or otherwise, I've come across none more worthwhile than his writeup. If you're interested in reading more about the Sigma DP1, my advice is to start here.
(Thanks to Yerg)