I'm working on a pcb layout and seeing whether we can't conduct heat out on the top layer, via the corners of the QFP.
This involves breaking the 1v8 ring in places so the ground pour can escape at the corners. Thats not a big problem because it can go on the bottom layer along with a 3v3 ring. But its the top layer that really lets the heat escape rather than fester.
The two large holes are solder nut supports (Pemnet SMTSO) for an option 25mm fan, if required.
Heres the layout so far