I am a huge Mars Volta fan. I recently found this on a fansite and thought it was interesting. Storm Thorgerson who had previously created the album artwork for the bands first two albums "Deloused in the Comatorium" and "Frances the Mute" was hired on to do a third cover (above) for the bands latest release "Amputechture" and although completed was never used. The band then went ahead with artist Jeff Jordan, using one of his artworks for the cover.
What funny about the story is that after using Storm's work for the first two, the band just broke off contact with Storm's camp:
"It's a bit like losing a girlfriend, and they won't tell you why"