This isn't reliability, it's functionality.
About the only power control circuits I can think of that could use normally closed power contact is a circuit breaker (fuse function) or motor starter (who's on first function). Both of these are motivated by the controlled source of power or it's physical effect, and the latter isn't really affecting the source, so much as it is signalling the load.
For signal level applications, potential damage to the switch itself, or the effects of normal power flow on the switch's ability to function are not usually a consideration.
I've worked on the development of an ultrafast multiphase transfer switch, with hybrid semiconductor/mechanical brush contacts, and it's automatic/manual control interface. At a certain power levels, you have to enforce your own 'fail safe' environment. Gravity, leaf springs or permanent magnets just don't cut it.
Isn't the apparent rarity of the requested hardware sufficient indication that the OP might be barking up the wrong tree?
RL