Over at IESB there's a video interview with Bruce Campbell in which he stated that Sam Raimi is extremely busy with the Spiderman franchise and who knows when he'd have the time or inclination to do Evil Dead IV.
And in case you think he was just being coy for the interview, I have independent verification of this from a source who spoke with Tom Sullivan. Tom did special effects work on Evil Dead I, II and Army of Darkness and is a friend of Bruce.
Bruce did say during the interview that he and Sam Raimi will be producing the upcoming remake of Evil Dead, but will leave the details to the director since the point is to see a different take on the original material. He joked about having Ashton Kutcher direct and star in the remake, and that if Kutcher wasn't available they'd try to get Ben Affleck, since Ben Stiller or Owen Wilson had already declined. :-)