From a gunamker's poitn of view, it is a good way to get very little for your labor. Making a gun to someone's specs is usually several times more profitable than building a spec gun and hoping it is what soemone wants. Now makers who are established and at the top of the field can do it and make money. But that is because these folks have spent years developing their skills and reputation, and their waiting list is years long.
I also am in 100% agreement with King et al that a gun that has been recased is a MAJOR turn off to me. I am firmly of the belief that a gun should only be recased when it is required for mechanical performance. CC'ing for "looks" is terrible in my view, and I will be very glad when this current fad of CC'ing any and everything will go away. If you need to reshape or engrave an action, then of course it will need to be recased. But if it was done just to ge "pretty colors" then for me the gun is worht less money.
