My primary objective for the 1284P is to get the additional RAM (and code space). Also needed to maintain the traditional Arduino dimensions and header locations, including ICSP. There is more then enough IO on an ATmega328 for my purposes....So all considered, it is built with my particular specifications in mind.
How did you estimate the area needed for the PCB heatsink?
Seems to be easier with the Variants folder now to implement a different mapping, need to look into that more.
I've been using iteadstudio and buying 10, 20, 50 boards.5cm x 5cm, $9.9010cm x 10cm, $24.90