I can't fully test this until my component cable comes, (using composite right now), but it does attempt to set it and ends up using 576i in an extremely cut off top half screen on my TV (trying to force 480p does the same thing, but in 480i mode). I'm not sure if that means anything, but if it would normally crash upon GSM executing the function call, my 50001/N phat is not crashing. I'll test this more when my component cables come next week.
Do you have any sort of "short list" as to which PS2s are known to work with 576p?
Sorry, but 576p is not implemented in the bios of any fat PS2, to our knowledge.