I've been selling PCBs for my USB isolator project for a few years now. It's a good cheap project, especially if you can get the isolator chip as a sample. (https://www.tindie.com/products/TomKeddie/usb-isolator-pcb-only/)

In 2015 Adafruit came out with a self powered isolator. We built some in a workshop at our hackspace, these are the PCBs we used. It is limited to 100mA so some Arduino designs (eg. with ethernet) will still need local power.

The Adafruit product can be found at https://www.adafruit.com/products/2107

The eagle files are at https://github.com/adafruit/Adafruit-USB-Isolator-PCB

A basic bom is shown here in the images, more details in the eagle files.