I have a couple of guitars which have had headstock repairs, one is my 64 Thunderbird IV bass and the other is my 63 Firebird III. Both have the same problem (long headstock, narrow nut, extremely long guitar), and it is really hard to find one that hasn't had a break. However both of them sound great. Will Scott rebuilt the Thunderbird (I bought it in pieces), and he inlaid the 6 laminate layers so it is really hard to see where the repair is. The Firebird was repaired already, but I was able to play it and tell that it had a great sound.
One thing though, a headstock repair (no matter how good), will not stop the headstock coming off again if the guitar is dropped. What will probably happen (as happened to the Thunderbird and to a friends 63 SG), is that the break will happen under the fingerboard, eventually forcing a scarfed on headstock.