Chris, I am afraid there is no proper solution for the problem you have mentioned.
Triacs are prone to be brokendown very easily in case of short circuit and even worse a broken triac mostly (90%) stays not in open circuit but conducts well uncontrolly. To use semiconductor fuses is rich man solution. They are much more expensive then of triac itself. Although it is a bit primitive, but a contactor serial with the triac (or SSR) would be a solution if your system have spare outputs to control the contactor as well as to check the triacs health.

Rustu