http://www.newegg.com/Product/Produc...82E16883220006
This has been a superb Observatory control computer and always on media server. It is basically an eeePC without a screen and has been upgraded to 2gb memory and windows 7 Ultimate (genuine!) - winxp recovery disks included.
If you are after a 12v low wattage computer that be the heart of your observatory, then you can have this for $250 posted to Oz.