and you probably don’t want to make the board exactly like the one you posted - add some decoupling caps on that board nice and close to the pins, rather than having the user of the board require placing them relatively far away.
E.g. SparkFun’s pure breakout board for the XMega100: https://www.sparkfun.com/products/9546
Could even add a crystal (though I’d make that user-customizable with some header pins) for the same reason, a la siphec.com 's breakouts for many microcontrollers: http://www.siphec.com/item/ATm128-TB1.2.html