It's here :
Nikon | News | Digital SLR camera D5200 Wireless Remote Controller WR-R10 Wireless Remote Controller WR-T10
It looks like you start with the D5100 and add:
- the 24Mpix sensor from the D3200
- the 35 point autofocus system from the D600/D7000
- the 2048 point exposure meter from the D600/D7000/D800/D4
And that gives you a consumer camera that starts to overshadow the D7000. Pretty serious stuff.