I feel like I have been searching for these for a while now and would just like to post a link for anyone looking to build a (resolution independant) HD video mixxer for under $2000 (US dollars).
I have ordered mine and already have a “shuttle on steroids” to put it in.
The two input card is around $1200 and the one input is around $800. They have wdm drivers so they will work flawlessly in VVVV. The mixer app should be easy for most of us here. And it doesn’t depend on “broadcast standards” you can throw most any arbitrary resolution at these and they keep separate two streams.
so here they are:
http://www.ems-imaging.com/catalog/modules.php?name=catalog&file=index&cPath=39