pin art automatic...

i am looking for a pin art system that is electronic i wish to be able to instruct each pin to move up and down a total of 100mm ideally i would have 2500 pins moving independantly of eachother so that they could build a 3d image on instruction and clear that image and do another image quickly. each pin must be able to go to 1 mm points between 100 and 0 so say 35 mm then 58mm then 1 mm then 100 mm i was thinking a a set of 50 rotating bars driven all the time in one direction and a another set of 50 rotating bars in the other direction arranged in a grid. so that the pins can be pushed or engaged with the bars to go up or down by small switchers until the righ t height is got to. I was thinking a motor and screw system might be one way to do it with each pin a screw as well. But i am open to suggestions there have been a few attempts to do this before and i have seen examples via google search "electronic pin art for example" The system must be fast The system must be cost effective