Thom Hogan has published his 2011 predictions (see source link below).
He expects the D4 to be announced by August 2011, which tracks well with prior releases.
He also predicts a new Nikon 18mp sensor with at least D3-like capability, maybe better. We'd be surprised if ISO performance was worse than the D3S, since this isn't an area you want to step backwards with your top of the line pro workhorse.
Thom also predicts a completely new AF system (the CAM 3500 will be 4 years old by then, so we'd be amazed if it didn't have a new AF system), and a better metering system upgraded from D7000.
Other predictions include hard core video features (obvious), Integrated GPS (not so sure), USB 3.0 (would make sense), and updated UDMA specs (again, makes sense).
Thom also poses the question "will Nikon release a D4h and D4x, or D4 only?". Assuming there is no D3Xs (he's not expecting one), the D3X will be coming up for its 3rd birthday by late summer 2011, and will be prime for an update. Putting out a D4X with the new AF system (and presumably new, higher-resolution sensor) around that time does make a lot of sense. But as he also points out, with the D700 replacement expected as well, that's a lot of new FX bodies in a short time to push into the lineup.
Source: Thom Hogan on 11/9/2010.
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