MX12 Lumamod
For all the geeks out there who still work with analog video and maybe even with a Panasonic MX 12 video mixer there is a nice tutorial about modding this device to get luma keying:
http://mgcjerry.net/Lumamod/
For technical specifications check out vjcentral.net/hardware/panasonic-wj-mx12
Yochanan Rauert aka Yochee is working as a VJ in Münster, Germany since 2002 and is the editor and founder of www.visual-society.com