There are tons of various development boards around the internet. If you are looking for one – might be this one will fit your needs. It is featured with
- ATMega32 MCU clocked at 16MHz;
- I2C EEPROM (64KBytes);
- 4-way Piano Switch;
- Reset and some LEDs;
- 2 x 40 pin DIL breakout connectors.
Board is 100x75mm size with tracks on both sides. Probably it is best to send Gerber files to your nearest PCB manufacturer and get professionally looking PCB.