There are solutions with fuses on all outputs and even telemetry warnings to report a short per output I use them also, but they only work up to 5A servo loads. This is enough for many planes, but not the really big planes or gas 3D planes. Double the fuses and you have a 10A system, which should be perfect for almost any RC plane.
So Richard, why should a 10A fuse not work? It would work for ALL planes, but you can make a model with fuses for the users who want them? Size does not increase (much, if any). When a servo shorts i have seen cables melt and burn resulting in a total system shutdown (other cables tied to faulty wire melted also). I understand that providing power is very important in a very high load setup but there should be other options. Yes the smaller servo's and wires do not pull enough current to trip the fuse maybe but then the issue is less important.
We can also add fuses to the servo cables in extensions, but i would like to see it in a powerbox directly. Then the powerbox can report faulty servo's.