I am surprised that the Fostex is that far off. I use a couple of Sony Minidisc recorders and they are dead-on accurate after an hour.
I just tried an iRiver 780 at a stage performance to pick up ambient sounds. Good thing, too, because one of my wireless mics died during the performance. I haven’t sync’ed it up to the video yet but it ran for a few minutes over two hours.
Steve Mann