You can buy a 3D printer now?
Not only can you buy a 3D printer now, but it seems to be an open-source design so there’s competition helping to keep the price down in “decent laptop” territory:
You could work out prototypes with sugru (new cool thing this year) and modeling clay. Sugru looks quite cool.
Oh and here’s a kickstarter project for a version under $500: http://www.kickstarter.com/projects/printrbot/printrbot-your-first-3d-printer