Here's the deal: I had a cut down NF shell that was spray painted silver, a tire valve, and some AT2K parts that I wanted to integrate into it. I ended up taking 4" of 300 psi, epoxying the tire valve in one end, epoxying an endcap with a hole in it over the tire valve, and epxoying an endcap with a smaller hole drilled in it on the other end. I then epoxied about 8" of vinyl tubing to the back of an AT2K's liquitron, and jury-rigged the metal release peice on the airtank to the trigger via some music wire and luck. After spray painting it silver (the NF shell was originally spray painted silver, but someone got their hands all over it, and was permanently sticky. So I gave it another coat.)
After my first attemp, which the tire valve blew off somewhere, I ended up using the endcap, which is stated above.
This design is just basically an AT2K with 4" of expanded airtank, stuffed into a NF shell. I suggest you to try it. Ranges are around 100' flat, 1' barrel, 1.5" stefan with single BB and hardly any hot glue dome.

Post your comments, suggestions, since I'm probably going to make another one, and questions, please.
~Sinfil