Following this blog post found a name of artist who works "as a free-lance concept artist at Quantic Dream on a secret project". It's hard to say if this project is Heavy Rain or it is forgotten Omikron 2, or maybe another one?
On my opinion his works more close to Omikron or even to Quark concepts.
If you follow his site Froghat Studios maybe his works will help you to find an answer.
Arts were taken from this site.
Source: "SKETCHTRAVEL" The World Traveler Book Blog