Hi. I won a bid on an XAduino board the other week. Just got it through the post and I thought I'd put up some info.
The Xmega chips are 8/16 bit and a little more powerful that Atmega. The reason I got this board was because of the onboard DAC and I have had good results with outputting waveforms so far.
The ebay listing is here (at this present time of Nov 2013.):
http://www.ebay.co.uk/itm/Arduino-compatiable-xmega-based-atxmega128A3U-/180922744611?pt=Motors_Automotive_Tools&hash=item2a1fd5ff23
There is a version of Arduino that works with the board and had extra libraries for DAC, Liquidcrystal, SD, Servo etc...
It connects via FTDI as a USB serial.
The site for the nfo & i downloads is here:
No hangups as yet and I can compile and upload main() as opposed to setup & loop using the modified Arduino IDE!
:0)