Where do you get this special USB device that reads the Hall sensor output of the odometer? That's a good idea, and I would like to see how this is done. Contact me privately if need be.
I don't see a way to get the odometer via OBD, but I can tell you that if it is available, the update speed can be increased way beyond three times a second with better equipment... but not in the $100 range perhaps.
How would you get fuel consumption data?