The PTC suggestion sounds like the way to go. As for the others - as mentioned, a short causes an input current of 0.8A. I need around 1A from its output (which is, I think, 50% little less than its normal max. current output). So if I add a 1A input fuse it would never blow. While I didn't check output short circuit current (will do though at the next opportunity), my understanding of these regs is that, upon an output short, the output current would not be enough to blow a 1A fuse, this being one of the ostensible features of the reg - no output fuse required.
>> Or do you have some sort of application in mind
>>that necessitates shorting the leads on the regulators?
I call it "preparing for the unexpected". While I don't design to cause short-circuits, in an imperfect world, and particularly with field-connected devices, it is an event that should be anticipated and allowed for, at least IMHO.
So while noone has directly anwsered my question, I assume that it is indeed normal for a 78xx reg to get extremely hot on a short-circuit? Please, a simple yes or no though!