Guy Kawasaki pointed me to this video of Chris Anderson talking about the topic of his next book–"the emerging world of free." His discussion of 3D printing technology got me thinking about how it might create a new class of inventors and innovation.
3D Printing in the World of Free. At 14:57 in the video, Chris states that 3D printing technology is introducing aspects of free into the world of physical products. He says 3D printing makes complexity free. Traditionally every bit of complexity in an item added more cost. However, every additional level of detail and complexity–i.e. grove in the surface–in a 3D printed item is free. The additional complexity cost nothing; the 3D printer head just takes a different path to make the detail required.
Chris says this ability to make physical complexity for free will dawn an "erra of impossibly detailed and fantastically complex products, which never would have made sense in the traditional manufacturing 
environment, but are now happening because the cost is now zero." Chris also touched on 3D printing in his first book, The Long Tail (see page 225).
Idea Lab is on the verge of releasing its Desktop Factory 3D Printer for $5000. At that price its targeted businesses and schools. A 5000 price seems a little steep for the mass market. But of course prices will come down.
3D Printing and Inventors. The Wall Street Journal has an article [no subscription required] discussing how companies are forming that use 3D printers to allow users to print 3D figures from online games. You create the figure and the company will print it and mail it to you. The article has this video that explains the state of the art of 3D printing. The video explains that the technology is not perfect, and the products created by a 3D printer may not be as refined and durable as desired. However, in the future it will be possible to create something of a computer or buy a product online, download instructions, and "print" the product right in your home. The video shows how a working flashlight can be printed using current technology. Certain 3D printers have the ability to print electronic components as well.
The pace of innovation and iterative invention will quicken when inventions or components of inventions can be quickly and cheaply printed and tested. So, will inventors purchase affordable 3D printers to prototype their inventions? I think so. As the price of 3D printers drop, the ability to easily create will increase the number of inventors and correspondingly the amount of innovation. Just as the web 2.0 has drawn many more to be participatory content creators, will 3D printers draw the masses to invention and create a new mass/class of inventors?