[cmos]

I noticed the other day that www.sparkfun.com does custom 3D design and prototype, though this probably isn't the cheapest option as you'll be paying them to make the design: http://www.sparkfun.com/commerce/static.php?name=custom_encl...

There are lots of premade 'enclosures' that you could hack apart to get what you want as well: http://www.boxenclosures.com/category/category.html

However, I would recommend something like the online services mentioned here that send you prototypes. Don't be intimidated.. just go through the tutorials and you'll be surprised at how easy it is.