I was sold the "last" Unity Flex Kit they had. From talking to the sales and service person (if you have dealt with NLT, you know who I am talking about), she said they are limiting sales on some parts they can no longer get because they do still have contracts to repair some of these units for agencies that haven't upgraded yet. With proper prodding, you may be able to get some of them, but it sounds like the supply is running very thin. I also asked if she knew of anyone other than them still supporting the XG100 and I was told there is no longer any official support and parts aren't being made. I have no reason to believe she wasn't being honest. I am glad I got a few spare sets before the supply dried up as I also have been rebuilding these for a couple of people I know.
They are really good units if you know how to very gently service them.