The folks at eMachineShop.com can make you an expert part designer and fabricator! Well, maybe not an expert, but if you've always wanted to be able to make custom parts for your car - a mounting bracket for some new electronics, say, or a slick adapter to mate two mismatched parts - this might be the way to go. (Check out the picture of the fuel pressure regulator adapter)
eMachineShop provides free CAD software that you can download, which gives you expert
design feedback instantly, computes an exact price in seconds and lets you conveniently order your part, in any quantity, via the web.
They support all sorts of materials, finishing and manufacturing methods, including injection molding, milling, turning, laser cutting, thermoforming, and many others.
No expensive CAD software to buy (and learn), no chasing all over town to find someone who can give you a quote on making your widget. Absolutely brilliant.