Yeah, stereolithography is a really exciting technology. Although I'm not close to it at all I do read the odd article in the engineering magazines about the latest big advance that's been made so I am aware that things have come a long way recently. I believe they've now got a process of fusing metallic powders using a laser, building up the part in layers (as is common to all the variants of rapid prototyping technology). The latest article said that they reckon that they're going to send one of these machines with a load of raw material(s) into space with each spacecraft so that they can make spare parts up there. Whether rapid prototyping will ever get to the stage where parts of sufficient integrity can be used for actual servicable use will remain to be seen. I'm sure we'll get there in the end . If you're interested in stereolithography then take a look at this, I think you'll find it interesting.