The Sparkfun Electronics Mega Pro is a full sized Arduino Mega2560, but without the USB to TTL converter and shield connectors. If you already know how to deal with USB to TTL cables, have one of the correct voltage (3.3V or 5.0V), and don't want connectors for shields, this is your board.
The power supply can deliver 200mA to 500mA, and runs on from 5V to 12V input. You don't have to worry about connecting it backwards because there is a protection circuit. The power select switch ("RAW" or "LIPO") can be used as a power on/off switch, unless you have power hooked up to both.
Although the link below is to the 5.0V version, there is a 3.3V version as well, and it can be found on the Sparkfun Mega Pro 3.3V page. The differences between the two boards are the voltage regulator and the crystal, since the ATmega2560 can only run 8MHz at 3.3V.
|Sparkfun Mega Pro|
|Operating Voltage||5 / 3.3|
|Test Current Draw|
|Web Site||Sparkfun Electronics|