Superannotation has gathered up some information on what Quantic Dream (Fahrenheit, Heavy Rain) may be up to next. Firstly Quantic Dream have registered a number of domains in Europe with the "word" fiv5, furthermore a note on LinkedIn lists a concept artist at Quantic Dream as working on FIVE and Infraworld. Infraworld, being the developer's fourth title and one that has been in concept phase for quite some time already. It also would appear as though Sony Computer Entertainment has registered the trademark Fiv5, so it would seem the partnership between Quantic Dream and Sony will continue with Fiv5.
So the news is Infraworld (thought to be canned) may still be alive and Quantic Dream are working with Sony on Fiv5. Interesting.