Tomcat has posted an interesting comparison between the Sigma DP1 and Olympus E3 in the ClubSNAP forums. Whereas I chose the E-420 and inexpensive 14-42mm kit lens for the sake of using the most compact gear for each format in our shootout, Tomcat chose to go with Olympus flagship E3 and the high end ZD 12-60mm f/2.8-4 zoom, which some of you may recall was "Lens of the Year" according to The Online Photographer this past January.

His comparison can be found here.

Addendum - My take on those crops is that some of the difference in apparent detail comes from the DP1 image being slightly oversharpened (even at the default setting) and the E3 file being undersharpened. I'm also wondering whether the Olympus lens has a touch of decentering, as the bottom left crop (#2) looks a bit worse than the bottom right (#4). Despite these issues, it seems clear that the Sigma is showing more detail in the corner and edge, with remarkably even performance across the frame for a wide open lens. The 12-60 likely needs to be stopped down a bit more to compete with the DP1 lens performance in the periphery.