That's an interesting idea. I loved my imac for portability while travelling to a "fixed location". I still have my iMac from 2011 with the box and foam it came in and with the carrying handle it makes it super easy to securely pack up and move.
I was about to comment that this really is too litte, too late, for too much money IMO but the idea of a large screen portable might actually have an audience.
What I've seen from my friends working in media is that they would never buy something like this. They know enough about the hardware they need that they wouldn't buy an all-in-one desktop when they can snag a laptop and if they need the render horsepower mac / radeon might not be their first choice.
I'm curious to see how this pans out... can't see it having much of a market appeal at the current hardware / price point unless I'm just under a rock and out of touch with what people are doing these days with $5k to burn on compute resources.