Ron, lots of rigs have been valued based on the kind of analysis you just made... but in over five years, I do not recall this subject being discussed in any detail from the point of view you have raised.
I am sure that a complete rig warrants more than the sum of its parts, but it is going to be very subjective on what that difference is... depending on the actual rig... how rare the type is... how long the buyer might take to accumulate all the pieces, etc. I can't see how you could produce an accurate "rule of thumb" on a value increase...
Just my
