Can you check if the position is updated if you restart modRana ?
Also, try to enable "Show gpsd debug output" in Options->Debug->GPS, modRana will start printing the information it gets from gpsd to stdout.
This certainly also possible - modRana already has a worker thread (in the location module that resides in modules/mod_location.py that reads position data from GPSD. The worker thread could be modified to connect to BlueNMEAs socket and parsing the NMEA sentences it provides. There is just a single stable source (BlueNMEA) without the usual quirks of standard GPS devices, the parsing should not be that difficult, at least for basic location data (latitude, longitude, elevation, speed, direction(?)).