>Heck, if they'd just nail that 24mp chip into a D300, it'd be >'job done'!
Or maybe not. There is no solid evidence that Nikon can move 24*8 mpx per second to the buffer. That's 192 mpx per second. Even the 2x+ more expensive D4 flagship sports camera only moves 160 mpx. That would put a D400, at the same bandwidth, at 6fps max. I think that would go over like a lead balloon.
The D3300 will probably have something like 36mpx, which would be an FX equivilent of about 80mpx, and surely the "D900" replacement for the D800 will have somewhere between 16 and 24 mpx DX density equivilent, and it will probably lag the "D3300" replacement for the D3200.
I'm suggesting that endlessly increasing resolution is directly in conflict with high frame rates, yet "D400" customers (and FX too) are demanding both, at least as a group. Some (most???) want it all, without thinking through the bandwidth issue.
My point is that it is not necessarily just a matter of sticking a 24 mpx sensor in the D300 case.
I'm a D300 shooter too, but I'm not sure how I feel about stuffing 1GB of images every 5 seconds of burst shooting into the card. I think the resolution is getting ahead of our ability to cope with the output, at least for those of us that do shoot 8fps.