Here's an interesting find. I was looking at the Bandai Hobby center site and found out that they use the Objet Eden 330 3-D printer for prototyping their Gundam kits during the design phase.
3D printers use CAD data in order to "printout" a rendering of an object in solid plastic. The benefits of this is that it speeds up the design-to-build process by being able to make a prototype that will test the validity of the CAD data before jumping right away to the more expensive process of machining the metal molds. It cuts cost by avoiding costly design mistakes as well as reduces the man-hours needed in designing.
According to the technical specs found at the Objet website, the 330 version boasts of the following pertinent specs:
Layer Thickness :16 microns
Build Size: 340 mm x 330mm x 200mm
Accuracy of 0.1-0.2mm
Weight: 410 kg
It doesn't say however what the speed of printing is, but the latest version of the Eden is the 350 and it can deposit about 20mm/hour of strips.
Aside from Bandai, some other model kit makers also use 3D printers in their model kit build process. One of which is Model Factory Hiro, who use their 3D printer in the mold making process when they design their car kits.
Commercial 3D printers like the Objet 330 are expensive however, but thanks to the open-source movement almost anybody can have their own 3D printer and make model parts at the comfort of their home. We have the Reprap project to thank for that, because they created an open source 3D printer design using off the shelf parts and gave the design away for free.
Of course you might say that you don't have the skills to build your own 3D machine even with the design schematics from the RepRap project, but that problem is solved with third party assemblers like Makerbot offering 3D printer kits that can be easily assembled like a (what else?) model kit. It will set you back about $1000~$2000 for one Open Source 3d printer kit.