Checkout this video where Toby presents the DIY DVI Mixer he is working on. He tells the tale of it's creation and then spills all the details: Two channel DVI mixing up to 1080p including "odd" TrippleHead resolutions like 1920x480. We can't wait to get our hands on this, it looks like a perfect mixer for VJ's. As more and more laptops are not equipped with analog TV-out anymore, DVI mixing becomes more and more a necessity.
Checkout all the details on tobyz.net