The contests I remember:
Remember The Name
The Catalyst
Lost In The Echo
A Light That Never Comes
Darker Than Blood
And there were the mash-up contests at lpconcerts.com.
"Burn It Down (Bobina Remix)" was a fan made remix the band liked and decided to release as part of "Living Things Remixed" (the tracks sent to people who pre-ordered the album).
LPU members also got a download of LPAssociation's Viscera (fan made remix album) for the anniversary of The Hunting Party.
There were also remix contests for Kick The Bass and Dreamland by Julien-K, but I know you're not going to list those.
Edit:
There's also that mash-up called "99 Steps Klosr" which was made before Collision Course was even recorded and received radio airplay. Warner even had an internal CD with it.