TheLostGamer, the latest issue of Official PlayStation Magazine UK contains a concrete answer from Quantic Dream founder David Cage about the possibility of a sequel to Heavy Rain. "I don't want to do a sequel because I've said what I had to say about these characters and this story," Cage explained, later adding, "honestly, I have nothing else to say."
If Quantic Dream wants Heavy Rain to provide a cinematic experience, it certainly makes sense not to drag the proceedings out over the course of a few games. Besides, it would be simply unfeasible for Heavy Rain 2 to import every single decision you made in first game. How's it supposed to remember every time we chose to juggle, watch TV and eat sandwiches instead of searching for our poor, kidnapped child?