Cell phones (like this and this) are turning out to be a reasonably popular open source project. It makes sense when someone points it out. They are pretty much the Swiss Army knife of the digital world. More importantly, they are useful and versatile but they don’t require any real hardware hacking. That’s important since most of the people doing open source work are comfortable with code and soldering irons…not wrenches.
Here’s an outline of the open source hardware necessary to physically assemble your own touchscreen phone. Zach Wick grabbed all of this stuff off-the-shelf (his or someone else’s).