Just trying x2go on fedora 20.
Starting a kde session, the display size is ignored. It takes the entire display. xdpyinfo reports: screen #0: dimensions: 1920x1200 pixels (423x264 millimeters) resolution: 115x115 dots per inch
The physical screen is (local X): screen #0: dimensions: 1680x1050 pixels (371x232 millimeters) resolution: 115x115 dots per inch