I think you are right. Probably it won't survive crank, I'm not even sure if it will boot upon ignition like the ITPS.
But you might look into the Carnetix powersupply. Actually the Carnetix is a not a powersupply but it is a powerregulator and startup/shutdown controller in one. Something like the ITPS but with the features of an Opus.
But i don't know how much it costs, you might find some further info here on the forum.