Here is another batch of G4 MDR-2s, just removed from use. I have been told these have the latest firmware and they are all tested and working. Serial numbers are in the 2000s. These are ready to use with your HU-3, and could be a great starting point for a Preston package!
Asking for $3200 Or Best Offer plus shipping (or local pickup in Philly or NYC)
Contact me at firstname.lastname@example.org if you are interested.