In this Korean forum, several alleged Fujifilm X100 sample pictures have been posted. Most are shot at 200 ISO, with some at higher ratings up to 6400. If these are real, image quality looks quite good. Mind these could be fakes, and that they’re reduced to web size where things tend to look much better than at 100% magnification.

Source: rangefinderforum.com

UPDATE: Even more X100 sample pics in this Japanese blog. Source: rangefinderforum.com.