BPF, I'm as much a stickler for the POH as the next guy, in fact the one of the a/c I mostly fly sits right next to me now.
However, nowhere in a POH have I yet found the phrase:
Brain - switch off
I would switch the master off PDQ also, but especially when flying in remote areas I'd really try to get a Mayday and an 'ident' out first. Obviously, if the flames are already licking at my feet I might not.....
Re the handheld - fuggetaboutit for most situations. Unless you have an external antenna and have it rigged and ready, these things just don't have the range required.
From AOPA Flight Training, referenced somewhere else on this thread:
If we have time to communicate before powering down the electrical system, we have three options. Call ATC, broadcast in the blind on the emergency frequency of 121.5 MHz, or tune the 7700 emergency code into the transponder and IDENT. Taking a few seconds to do any of these things before we shut down the electrical system might alert someone to the problem and bring fire/rescue services to the scene as we head for an airport. Finally, if it has a manual switch, we can activate the emergency locator transmitter. The beauty of the ELT is that it has its own power supply and will bring help to the scene of a forced landing should that become necessary.
Makes sense to me.