Here you go Sam, this is what I did with a 4500 psi nitrogen cylinder. Take a standard Air Force scuba adapter, remove the K valve adapter, and install whatever CGA nut and nipple you need to mate up to your tank. The first pic is the stock adapter, the second is after mod and installed. One note, I'm pretty sure it can only be done with this style of scuba clamp. Any more questions, let me know.
Dave