While the quadcopter based on an AVR 32u4 is working (with the exception of one annoying bug that I have yet to track down), I am pushing the limits of the 8 bit microcontroller. I figured that this would be the perfect excuse to get into ARM programming.
We have designed a new flight controller board that uses an STM32F410 chip, which has tons of pins, cycles, and an FPU. The boards have just arrived on Friday, and we plan on making the Digikey order today or tomorrow.
The new boards do not have an integrated frame. They have a standard mounting hole pattern (45mm square) so they can be used with commercial frames, and I am planning on making one out of balsa wood. They support up to 8 motors (octocopter), and can drive either brushed (directly) or brushless (via ESC) motors.
The board image is below; stay tuned for updates...