What exactly do you what to do?
I use avtake for broadcast and it works great. I use it with four z1 cameras never any problem.
For HD in cutfour you need to use either blackmagic or decklink cards and at least an I7 800 or 900 series mobo.
All in all it will come out at half of what a low end
HD switcher might cost plus you get added features only available in higher end hard swicthers.
You can download a demo for the hd mixer but you need to have at least a decklink card in your system.
You can also check tricaster they got a 3 camera hd/sd switcher system for about 14k.
Good luck, Let us know what you found.
RC