This would be great for prototypes and limited prodution products. Use a mini USB B connector in the same place as the SMA connector. The handshake lines from the USB chip could go to solder pads at the end of the board opposite the USB connector. Use .1 spacing so a pin header could be user installed for easy connection if needed (usually not). The new FT232RL may be a good choice. I didn’t see a BOB for this chip yet.