Videomaker – Learn video production and editing, camera reviews › Forums › Cameras and Camcorders › DSLR’s › Clean HDMI Out › Hi electrodog10,
There certainly are SLRs that can do this. The Canon 5D Mark III recently had a new firmware version release that allowed cinematographers to record a clean 1080p signal out of it's HDMI port: http://www.usa.canon.com/cusa/consumer/standard_display/EOS5DM3_firmware
In addition, Canon also added a clean HDMI out on their new Cine line meaning that the Canon 1DC also has a clean HDMI out: http://cinemaeos.usa.canon.com/products.php?type=Camera-1DC
As for Nikon, many of their DSLR's can put out a clean signal over HDMI. The Nikon D600: http://www.nikonusa.com/en/Nikon-Products/Product/Digital-SLR-Cameras/25488/D600.html, D800: http://www.nikonusa.com/en/Nikon-Products/Product/Digital-SLR-Cameras/25480/D800.html, D4: http://www.nikonusa.com/en/Nikon-Products/Product/Digital-SLR-Cameras/25482/D4.html, D5200: http://imaging.nikon.com/lineup/dslr/d5200/, and D7100: http://www.nikonusa.com/en/Nikon-Products/Product/Digital-SLR-Cameras/1513/D7100.html are all able to output a clean signal over HDMI.
Lastly, the Panasonic GH2: http://panasonic.net/avc/lumix/systemcamera/gms/gh2/ and GH3: http://panasonic.net/avc/lumix/systemcamera/gms/gh3/ also have a clean HDMI out if you like those products better.
Hope that helps and good luck!