I've done a bunch of tests at different ISOs. Here's just one of many examples. This camera definitely produces some sharp enough images, at least for me.
ISO 100, RAW processed in CS5 (ACR 6.7). All I did in CameraRaw was slight increase of clarity contrast, and then some USM in CS5.
edit: most of you probably know this but some may not. To see the full picture, click the link right under the picture and once the image opens, zoom in to 100%.