The MCP2200 is a USB-to-UART serial converter device.
It is getting a bit on the old side, only supporting USB 2.0, and all the software support provided is Windows-only.
Nevertheless, I got hold of the MCP2200 Breakout Module to find out more.
I was particularly intersted to see how far I could get under MacOSX, including configuration over the HID Interface.
The answer is pleasantly: all the way!
As always, all notes, schematics and code are in the Little Electronics & Arduino Projects repo on GitHub