Interesting... And awesome. It would be like the Canon 5DMK2 big brother. This would be a great studio camera and a pretty good 'everyday' camera if you use smaller RAW file sizes. At 5fps, that's good for just about anything. I love the high ISO of the 5DMK3 for some of the evening work I do, but they made too many compromises in it (no user-replaceable focus screen, slow SD card performance, no built-in WiFi)
With the price of the 5DMK3 dropping like a rock, we could see the price on that camera be between $2500 - $2700 a year from now. Which is the price I thought it should've been from the beginning. The 46MP monster would be priced around $3500 - $4000 I would think.
While expensive, this could be the camera I wanted the 5DMK3 to be. For non-magazine work, I would just step down the RAW sizes. I would think that for the price and the market this would be geared for, it would have dual CF slots and replaceable focus screen for expensive, manual focus fast primes. Hopefully it comes with an AF system equal to the 7D or better for those times when I need it.
I eagerly await for October....