PCB

    For different reasons I didn't want to use both sides for components. And, of course to make it smaller, I've used 0603 type SMD components, which made it easier to route but harder to solder. Because of tight space, some of the vias are placed directly onto components pads.
I was able to get 50x13 mm board :).

Top side:

Bottom side:

In order to have a reliable USB connection, the thickness of the board have to be about 2 mm.

Eagle files can be downloaded here.