I wonder if it is the same case with the Mimo 720 S touchscreen. It uses the same DisplayLink driver that you linked to. It works only if you boot up a Mac with a real monitor. After you boot, you can remove the real monitor and the Mimo will function as the only monitor until sleep or reboot. The Mimo 720 S is only USB and will not work as an only monitor.
Does the 8" Lilliput touchscreen work as the only monitor?