I'm also interested in a similar project. My thought was for MOSFETs upstream of a relay. If the MOSFETs blow up and fail shorted, the relay will save the day.
I would use a fuse instead of a relay as the fail-safe.
I think I would use a pair of back-to-back power MOSFETs to switch AC directly with a photovoltaic optocoupler to supply the turn-on bias. For a fast turn-off, I would include a separate optocoupler to drive an SCR (probably a pair of bipolar transistors making an SCR) to short out the gate drive. Now the control circuit is completely galvanically isolated from the power switch, so it can be placed anywhere convenient to measure the current.
Big TO-247 power MOSFETs are not too expensive and I think would survive shorting out a 15 or 20 amp standard 120 volt AC circuit until a fuse blew or breaker tripped.