*sigh* this question has been asked to death. please look before you post. also it would break many copyright laws if someone was even able to put direct x 10 on xp;plus there would be many compatibility issues.
Vista DX10 isn't even working yet, as far as anyone here can prove. Let's wait until we actually have some drivers, games and apps before we start making requests for hacks.
Is it possible? Yes, if Microsoft can maneuver Intel integrated support into Vista, someone could hack DX10 into XP. Even if it's under a wrapper, I think it's highly probable.