The thing I see missing is the HorizSync and VertRefresh listed under your monitor section. I don't know if that would necessarily fix your problem, but it seems to be a possibility.
Try copying Rick422' HoziSync and VertRefresh settings. They should work.
Backup your XF86Config file and try running 'xf86config' from the command line. Oh, and to set your moitor at 70 Hz
Modes "1280x1024/70" "800x600" "640x480"
I think, somebody correct me if I'm wrong
Try that I guess...