Discussing the current state of video-capable DSLR cameras
Note: There's a summary for the impatient!
In August 2008 Nikon released the D90, the video DSLR that shot HD video.
The concept was apparently aimed at news-gathering, where reporters who would usually have to carry both a DSLR for photos and a separate video camera, could instead carry a single device capable of both shooting stills and, at the press of a button, shoot HD video.
For completely different reasons, these VDSLRs also appealed to film makers - a wide range of changeable, affordable lenses and large sensors capable of creating "filmic" shallow depth of field.. but, film-makers and news-gatherers have very different needs, and all VDSLR's thus far have been, in various ways, broken..