Here are the design files for the TIU Signal Tester. Included are the Gerber files for PCB fabrication, the Diptrace files to tinker with the design, and the BOM for ordering parts. There are several other ZIP files in the overall ZIP file, the Diptrace files and the Gerber files are all separated out. I did flip the pot around in this design as it was backwards in my original boards.
TIU Signal Tester Design Files.zip
You don't have to use the exact parts I used, they're all sourced at Digikey. Most of the parts are very generic, and for any kind of quantity, you can probably find cheap eBay parts. However, the BOM does give you industry standard parts and specs so you know what to look for. Even sourcing them from Digikey, they'd be pretty cheap. Stuff like the 2K pot will probably want to be the exact part as it fits the PCB footprint. Have fun! 
