The Smoke 2012 demo in AJA's booth was an Io XT and iMac. The Autodesk demo artist was amazed how snappy it was. An Io XT is basically a Kona 3. (Not 3G mind you). But 3... AFAIK is the only one that loops TB cables too. So with a laptop, you could still have a second computer display with it. So if you're working in 4k, you're only solution for post is a card and tower today. Bet that changes by next year. AJA's Ki Pro 4k box is Thunderbolt. You can capture raw DPX files with it.
I think the whole group at NAB came to the realization that Towers are transitioning away from us all. Macs and before long PC's. I've a blog about this:
http://blogs.creativecow.net/blog/11482/nab-2012-the-mayans-had-it-right-it...
Jerry
