Challenge : Best 3D printer ever...

Actually this is something I have been thinking about myself as well, since you'd obviously have to have some sort of liquid feed mechanism - instead of the standard geardrive and heated emitter, I imagine you'd need a heated tank to keep the chocolate at an ideal level (adjusted and regulated differently per type of chocolate so that it wouldn't become too viscous) and then also maintain said temperature of the liquified chocolate until it reaches the nozzle, and also some way to control/regulate the flow and cutoff at the nozzle. I second this idea, actually. It would be awesome to be able to print 3D chocolate custom sculptures. (And could in fact be adapted over to other sorts of candy easily enough, you'd just have to stick with something that has a similar viscosity at a not-too-far separated temperature, or just use higher-tolerance nozzle/pipes/etc.)

Actually this is something I have been thinking about myself as well, since you'd obviously have to have some sort of liquid feed mechanism - instead of the standard geardrive and heated emitter, I imagine you'd need a heated tank to keep the chocolate at an ideal level (adjusted and regulated differently per type of chocolate so that it wouldn't become too viscous) and then also maintain said temperature of the liquified chocolate until it reaches the nozzle, and also some way to control/regulate the flow and cutoff at the nozzle. I second this idea, actually. It would be awesome to be able to print 3D chocolate custom sculptures. (And could in fact be adapted over to other sorts of candy easily enough, you'd just have to stick with something that has a similar viscosity at a not-too-far separated temperature, or just use higher-tolerance nozzle/pipes/etc.)

I think the chocolate is the hardest part of the project.  You need a chocolate that would cool quickly at room temperature, yet still be tasty.  Other than that, maybe a marble table?  I'm not a chocolatier, but this project sounds good!  I think I remember seeing someone making a frosting extruder, if I can find the link I'll post it up.