Recently I've seen emails from manufacturers advertising "all In One" cameras. The text from one such email is below:
"This is [never heard of before] company, the top manufacturer of CCTV Camera and DVR in China for 9 years.
Now the new technology of CCTV Camera is launched, which is called 4 in 1 camera (720P, 960P, 1080P). This kind of camera can be changed into analog, AHD, CVI, TVI signal by OSD Cable and very popular on the market now, because it has four camera signals which can be changed into each other.
1.Keep holding the OSD button any side to switch
2.Plug in the power supply
3.Release the OSD button when the video display"
I've also seen at least one DVR that accepts TVI, Analog and AHD on any BNC.
UPDATE: See Beware: The Magical HD Analog Converter