and cheap 4k ability available next month.What do you mean by this? When you say "cheap 4k ability", I think "recording 4K to flash cards", like the Panasonic GH4.
But I haven't heard of such an announcement; is it something else?
I'm talking about the Atomos Shogun. It allows the A7s to record 24fps at 4k ProRes 4:2:2. It's $2,000.00 for the recorder and $2,500.00 for the A7s, so that's $5,500.00 for absolutely beautiful 4k with the best lowlight in the business. Just don't plan on shooting any action sequences with it, the rolling shutter is horrid.
But, that's relatively cheap 4k. Not flashcard cheap though; that would be great.