This us a terrific camera, top-of-the-line for Sigma, and other Sigma cameras are supported, but not this one--at least so far. SD1 users are forced to rely on Sigma's RAW converter, PhotoPro, which is free, but only allows tweaking of various color attributes. No spot removal, no cloning, no ability to create layers, etc.
Thanks; I added my vote. Reading through the comments on this issue, a couple of people have referred to the existence of another RAW converter from "a small company" that will read SD1 files, but no mention of a name. Do you know what it is? If you'd like to reply offline, I'm email@example.com.