Nikon may have confirmed the existence of an upcoming mid-range DSLR through a product image on its site which was removed later on. The LCD screen capture explaining histograms identifies the camera as a D300s and makes reference to SD card storage where the current D300 uses CompactFlash.

These changes appear to support rumors of the D300s being a high-speed camera which could shoot continuously at 8 frames per second with a battery grip, instead of only in bursts, and which would have both CompactFlash and SD to give a choice of storage as well as to provide overflow space.
The photo being previewed in the capture is also dated May 14th, hinting that Nikon has only just recently processed the capture and that the camera maker is nearing a release for the D300s.

Other features rumored and now seemingly known for the D300s should include 720p video recording with features that haven’t been avaiable in the D90 or D5000, such as contrast-based autofocusing and support for an external microphone. It would also have a new quiet shutter mode for sensitive nature photography and enhanced D-Lighting (dynamic range adjustment) that involve both extra-high and fully automatic modes. The actual dates of release is unknown but it should be out announce real soon.

Via electronista