I was shopping for SLither and came across a hybrid double-sided disc with HD format on one side, standard DVD on the other.

amazon link

Never even haerd of this, and I might get it because I plan to get an HD player soon (one that plays xvid ).

Yes, this is common. Can't really see the point though. If you've got a HD player, you don't need the SD side, and if you've got a SD player, you can't play the HD side.

Should tide people over who don't want to double dip once they buy a HD player.

It beats buying it again, its only $10USD more than the DVD. I don't know anyone with an HD player yet though, so a year from now I might get to actually watch that side.

Unless Blu-Ray wins and no one you know buys an HD-DVD player. Or better yet, neither one wins and they both die like Laserdiscs.