Andrew Plumb (aka aplumb and clothbot) has been experimenting with making LEGO-compatible blocks for awhile. We talked about his work on here back in December, and he has done some more great work since then. Our last post mentioned the laser cutting files he uploaded to Thingiverse, and above you can see some of those digital files made real with our own beloved laser cutting service, Ponoko Designmake.
He has also had some parts 3D printed through Shapeways, and they are even available for sale through his Shapeways Shop.
Custom LEGOs… oh to be 7 years old again (with access to a 3d printer).