Well, I got tired of filling with the hand pump during long shooting days. It's great exercise but having to rest for several minutes before I can actually shoot after filling was getting to me.
Any way, I bought a SCUBA tank and ordered a fill adapter from Pyramyd. The one they sent is machined from a block of aluminum and the machining is pretty sloppy. The pressure release valve does not seat fully so no matter what you do, some air leaks out during a fill. The hose is only about 1 foot in length but that seems to be some sort of unofficial standard...not sure why.
Today, I went back to the SCUBA shop and got a stainless steel valve assembly then went straight to my local "Parker hose" retailer and had them make up a 3 foot hose rated to 6000 PSI. Now I can fill without so much loss from a badly seated valve. It was expensive! The fill yoke cost $100 and the hose another $25 but I think it's worth it.
Hope this helps someone trying to decide on adapters and yokes.