Cool, I know this guy. He was telling me two months ago he had to go to the UK for a job at Rare (he has worked for Ubisoft before, he's a freelancer). A few weeks ago he came back, the project was cancelled.
http://67.227.255.239/forum/showpost.php?p=37207200&postcount=1744
I actually doubt Gilles Ketting would post concept art of a Rare Ltd project, especially if it's unannounced.