Frustrated by a lack of stock of adafruits breakout boards for the atmega32u4, I decided to design my own.  Yes, I could buy a teensy, but a teensy has (what I consider) a design flaw in that it has pins on the end which cannot be breadboarded.  The arduino leonardo is overpriced and a pain to connect to a breadboard.

Features:

• Atmega32u4 with all non power or ground pins broken out to header pins on edges of board
• 3.3V regulator on board broken out to header pins, for powering 3.3V devices
• The easiest-to-solder SMD USB mini B connector I could find
• NX5032GA-16.000000MHZ crystal for full speed USB development.  Woah, thats a lot of 0s
• Broken out Atmel ISP header
• Button to reset chip for bootloader

And of course, it is breadboardable and fabbed by the fabulous OSH Park, on sweet purple and gold boards (.063″ thick). The final thing to do is to throw the silkscreen layer on there, so you know what pin is what!  All the files for this board can be found in the downloads section, including a BOM ($13 at qty 25) and gerbers.