I doubt we'd be able to take any old USB stick and turn it into a dongle. USB flasdrives are mostly SSD memory, whereas dongles have an EPROM or EEPROM flashed with a specific firmware/set of files.
It might be easier to take an existing dongle (I have a FlexLM-based dongle for FlexiSign), and possibly rewrite the firmware on the chip to emulate the dongle, unless someone comes up with an easy-enough-to-do hardware solution. If someone wants to try rewriting an existing dongle using a HW programmer, I'd be happy to donate my old Flexi one.
Here is the dongle.