check out this site, lots of samples that can be 3D printed in plastic of different colours

I don't want to release the project I am working on just yet, but the site will give you an idea and it's just size and imagination from there
http://www.thingiverse.com

then there is shapeways that say if I do a design and list it there that you buy the print off them not just in plastic but in various other materials like resin and metal.
http://www.shapeways.com/search?q=pinball&s=20#more-products

Ahhh, very cool.  Some of the items on shapeways seem a bit pricey though.  Who decides on the price, the designer or them?

I can see the 3D printing opening up a whole other world of mods.  Thinking caps on.