Look what I’ve just found in the Sigma SLR Talk forum on dpreview.com:

Major mirrorless camera rumor sites — as well as the visitors of above named forum — speculate as to whether this could be an official Sigma product. Well, I doubt that very much. It looks to be a Sigma DP camera which has been stripped of its lens and fitted with a third-party M-mount adaptor. Still, it might actually be a commercially done conversion, and if so, you might be able to purchase one soon. Wouldn’t that be cool? Finally, you could use your magnificent M glass with an equallly magnificent Foveon sensor! I’ll keep you updated in case this turns out to be an actual product …