I do a bit of rod building..I'd say it's not impossible.. but not very practical imo.. A modern style blank-to-blank ferrule is not going to happen.. no custom builders to my knowledge would have the ability to re-manufacture the blank in that manner.. all you could really hope for is an old-school metal ferrule.. which would certainly work.. the metal ferrules create a rigid "dead spot" in the rod..which is why they have been supplanted.. so it certainly wont make the rod perform any better.. but again, it will work..should not be too costly... call some local builders and see what they say.. actually a pretty ez job if you wanted to try it yourself.. just need to take a deep breath and cut your rod in half..

.. then measure the blank diameter at the split, order the right size ferrule from Mudhole or the like, and epoxy it in place.. good luck!