1280 pixel mode is a bog standard video mode.
Any monitor that doesn't support it is either
A: A ripoff piece of crap
B: Very very very old
C: Broken
Yes, 1280x256 and 1280x512 interlaced works on every PAL monitor and TV that I have. It's the same kHz and Hz as the normal PAL or NTSC modes. No scandoubling no nothing... just plain PAL/NTSC.
It looks truly amazing on a PAL LCD TV since those monitors doesn't show the flickering that the Interlace mode produce.