There's a module available here, and there are links on the page to documentation - I'm sorry I didn't reply sooner - I don't check this forum very often.
Thanks guys for taking note of this! Unfortunately the project I was looking at these for has since fallen through, though these may be useful in the future.
Comments
https://www.tindie.com/products/matzelectronics/ch559-usb-host-to-uart-bridge-module/
Edit, sorry - I misunderstood the requirements.
PIC Based but works really well.
The VNC2 is only about $4, see the V2DIP2-32 datasheet for a layout of a module.
Thanks guys for taking note of this! Unfortunately the project I was looking at these for has since fallen through, though these may be useful in the future.