MultiWii

IMU6410-10 10 DOF IMU Sensor Platform with ATmega1284P USB Arduino Bootloader

Now this is pure temptation!!!

http://www.ebay.com/itm/IMU6410-10-10-D ... 35b7b4f535

only 8 analog and 14 digital I/O pins - same as promini/nano. 4K EEPROM, 16K SRAM sounds tempting.32.756KHz vs. 11.0592MHz crystal may require some code tweaking - not sure what the actual code will run at.
If you are up to some code tweaking with sensor addresses, pin asignment, timers and timing, then go for it. The 1M flash could be fun.
The signal levels are not TTL but 3V or 3V3. should work with most ESCs but about servos?

As an alternative get an arduino mega 2560 and a 10dof board separately at approx. equal cost.

so yes, a mild temptation for the faint hearted like myself.

and some pins are used to interface the sensors. So mayibe not that good an option after all?

I kinda figured it was too good to be true, but I still find it very interesting to the number of the All-in-one IMUs making their entree into the market place.