I did a little more thinking on the CFX carbine idea. The biggest obsctacle actually turns out to be the cocking arm. I pulled the latch off my .177 to see what the mechanism underneath is like. It is a simple, elegant piece of engineering. The cocking rod is turned down to a slightly smaller diameter to act as the guide rod for the latch. The spring for the latch sits a recess in the end of the rod. The rod is drilled out and tapped for the retaining screw about an inch or a bit more on the turned down section. This works well and is simple, but would require that the rod be machined down and drilled and tapped again once cut.
All this would be easy enough to do if one had a lathe and drill press, I don't. The other altenative is to cut the very end of the rod off at the end of the turned down section, or just behind and then have it welded back on the rod once cut to length for the shorter set up, but once again, I am no welder and don't have the equipment. I'm sure I could find several places in town that could do the machine work or welding for me, but then, up goes the cost.
Oh well, it was a nice idea.