Somebody tried to sell me a rapid prototyping workcell. It was pretty darned neat and it would have been a great toy, but I couldn't justifying buying such a device for our company.

Their processs involved curing plastics that were dyed in multiple colors. Great technology, but personally, I prefer the use of laminated materials. It permits the use of a wide range of functional materials such as aluminum. IT even permits the use of transparent materials such as plexiglas. Very cool.