assuming your scene has two locators at the bottom called H1 and h2 (for tilt and lowest possible point) and Floor (fro rolling up) and 10 blinds named pPlane1 to pPlane10. then you would be able to use a expression like so
// blinds demo (c) joojaa 2012
// this is a expression for 10 blinds
//
// licence: Creative Commons Attribution
float $floor=Floor.translateY;
$H1=H1.translateY;
$H2=H2.translateY;
float $rot[], $trans[];
$numBlinds = 10;
for($i=0;$i<$numBlinds;$i++){
$ang = max($floor,$H1)-max($floor,$H2);
if ($ang>1) $ang = 1;
else if ($ang<-1) $ang=-1;
$rot[$i] = asind($ang/1.0);
$trans[$i] = max($floor, $H1 );
$H1 = $H1 + 0.3;
$H2 = $H2 + 0.3;
$floor = $floor + 0.03;
}
pPlane1.rotateX = $rot[0];
pPlane1.translateY = $trans[0];
pPlane2.rotateX = $rot[1];
pPlane2.translateY = $trans[1];
pPlane3.rotateX = $rot[2];
pPlane3.translateY = $trans[2];
pPlane4.rotateX = $rot[3];
pPlane4.translateY = $trans[3];
pPlane5.rotateX = $rot[4];
pPlane5.translateY = $trans[4];
pPlane6.rotateX = $rot[5];
pPlane6.translateY = $trans[5];
pPlane7.rotateX = $rot[6];
pPlane7.translateY = $trans[6];
pPlane8.rotateX = $rot[7];
pPlane8.translateY = $trans[7];
pPlane9.rotateX = $rot[8];
pPlane9.translateY = $trans[8];
pPlane10.rotateX = $rot[9];
pPlane10.translateY = $trans[9];
// add any amount of blind pairs
feel free to add any number of binds at the end and change the number of blinds in $numBlinds. Feel free to adjust the separation value of 0.3 and the bunching up separation of 0.03 and the length of blind 1.0. How sloppy of me as to not use variables. 
PS: This is a ad hoc simulation i made last time somebody asked.
