unfortunately the only way to do this with the software renderer or mentalray is to create a square for each frame of your image sequence and then cycle through the squares using the object index
below is a mel script I wrote that copies a shader with one image assigned to it from a sequence and then makes a copy of a plane and assigns the shader to it.
So you initial shader in this case is called burnt.
The script copies the shader called burnt and then increments the image mapped to and assigns the shader to a duplicate of
CODE
$x=1;
$shadername="burnt";
$imagesequence="sourceimages/burnt/burnt.";
$object="pPlane1";
$maxCopies=50;
while($x<=$maxCopies){
$result = duplicate -upstreamNodes $shadername;
print $result[3];
setAttr -type "string" ($result[3]+".fileTextureName") ($imagesequence+$x+".tga");
select $object;
$dupe = duplicate -rr;
sets -e -forceElement ($shadername+$x) $dupe[0];
$x++;
}