So BlackMagic does not do multi channel in? Like 4 video-in on a card... I don't mind evan using the BNC from my Canon Xl2... As I don't have 3 extra PCIe for 3 different card...
I have some cards (about 10) from my previous job that have 1 to 16 inputs via dongle (these card are used for surveillance video)... I'll install one of them in my pc and take a snapshot. I know windows sees them as input card... I could send you one if you want to check them out...
There are 4 chips on them and each is able to capture 30 fps... Total of 120 fps... They are PCIe 1x...
http://www.isscctv.com/videocards/cards/
TVISS4E is the one I have...