Bill Davidson (the custom frame builder since the 70s) advised me to use Araldite 2014 on carbon to carbon rebonding.
Also, imo bonded alu-CF fails about as often as bonded alu-alu. The worst thing you can do is buy a frame that has been crashed or previously damaged, but realistically you need'nt avoid Carbon Fiber bikes like the plague. Just do some research and try your best to find the supreme example of the bike you are looking for, don't settle for an abused CF bike, but you shouldnt settle on any abused bike if you are thinking of pushing it hard and not planning on repairing it.
It has proved itself a viable material by being available to the market for 25+ years.
i know this is a vintage specific forum but how long should a new technology be available before you can trust it?
After all there are still 20 year old full Carbon frames riding around without a problem today.
/rant