the dimensions are in the config.wtf called gxResolution. this would be the only resolution field noodled with when you use the region editor/maximizer.

changing the resolution in game would be enough and should reflect in the login screen. try running your wow without going through keyclone, after you reset the resolution (make sure keyclone was not running when you reset the resolution). at that point, keyclone has zero impact on the graphics settings.