there are quite a few in existance incl

Tiesto - Urban Train
Oceanlab - Sattelite
Matt Darey - Voice Of An Angel
Matt Darey - Liberation
Holden and Thompson - Nothing
Baby D - Let Me Be Your Fantasy
Faithless - Insomnia
Faithless - God Is A Dj
Jan Johnston - Skydive
Jan Johnston - Calling Your Name

Loads more to


as for sites acapellas4u.co.uk used to have them, now its shut down..