I have researched this topic in the past as I have two HD zones I would like to feed from a single player. I can't remember the specifics, however, even the players that do allow simultaneous outputs seem to indicate that when HDMI is being used, any component signals out will be significantly downgraded to the point where you might as well just use the composite output. I have finally conceded and am just going to get two seperate players. I am not sure if that is on all HD media but I know there are at least certain discs that will require downgrading. Like I said though, it has been a while since I looked into the topic so it is all a bit fuzzy. Keep us updated on if you find any thing that doesn't cost a fortune.
Matt