Bethesda have confirmed via Kotaku that the long wait for Doom 4 will be much longer still, but that it is still coming... eventually. Apparently they're now working on an entirely 'new version' of the game for next generation platforms, which has pushed the release date back even further, despite the game having been in the works for five years already. 'Development is not going well', their source concludes.
Rage 2, on the other hand, has been canned. The original title failed to meet sales expectations so the sequel project was cancelled, their DLC plans scaled back, and all id staff put to work on Doom 4 instead.