I know this isn't a mashup, but you definately should check out this guy ... he's awesome! 
"Lady GaGa feat. Khaleel - LoveGame (S.I.R. Remix)"
http://www.youtube.com/watch?v=fZiS5YpEp6Y
Written by Stefani Germanotta [Lady GaGa], Nadir Khayat [RedOne], Khaleel Deal & S.I.R. :mrgreen:
TAKEN FROM THE ALBUM "STRICTLY SENSUAL"
Link: http://blogs.myspace.com/index.cfm?fuseaction=blog.view&friendId=383884654&blogId=538594782
"Lady GaGa feat. Khaleel - LoveGame (S.I.R. Remix)"
Written by Stefani Germanotta [Lady GaGa], Nadir Khayat [RedOne], Khaleel Deal & S.I.R. :mrgreen:
TAKEN FROM THE ALBUM "STRICTLY SENSUAL"
Link: http://blogs.myspace.com/index.cfm?fuseaction=blog.view&friendId=383884654&blogId=538594782