FAN MIXES:
Here's a list of unofficial remixes done by fans of the group:

Cascade:
Hi-NRG 303 Remix by SG


Dirty Shadows:
Second Thought Remix


Elysian Feels:
Cubus Spiritrev4 Mix
Dr_Strange Remix
Elysian Feels... Good remix by jc13
Emoticon's Hippy Dippy Mix
Exhibition Remix
Full-source Remix
Funex Remix by jc13
Institute For Psychic Reform Papua New Guinea Remix
Mindstripper Mix
Second Thought Remix
Shorty Pop Mix by Shiny Things Network
Sonusea Remix
Virtues of a Heroic Death (Elysian Feels) by Realistic
X:FStm Eval


Her Face Forms in Summertime:
MFB Mix


Glass:
MFB Mix


Lifeforms:
Xenomorph Mix by Otep 147


Mountain Goat:
Full-source Remix


My Kingdom:
Full-source 2001 Remix
Second Thought 2001 Remix


Papua New Guinea:

=D Remix
Apex Remix
Bigobrain Remix
Christopher Micali Remix
Full-Source 2001 Remix
Institute For Psychic Reform Remix 1
Kvagga Remix
Matt Collins Remix
MFB Mix
Raila Remix
Rando Majestic Remix
Second Thought 2001 Remix
Siriunson's Remix
The Erb Remix

We Have Explosive:
DJ Dekan Remix
Full-source 2002 Mix
MFB Mix
Smirkoff Mix (Semi-official)
ReExloded By The Rebeat
Flapjack Remix



More info on fan mixes can be found at the FSOL Fan Mix site - thanks to Tim for info and help.