This is an interesting table....
http://www.paradiso-design.net/TVsystems_worldwide.html

according to this site

NTSC M has

525   lines
59.94 Hz/59.94 fields/s (Vsync)
15734 Hz Hsync

and PAL (many of them) has

625 lines
50 Hz/50 fields/s (Vsync)
15625 Hz Hsync

I think it is time to experimnet...(for who has a real HW)