Well, I'll tell you what I do. I'm a lowly private pilot, so I have to rent. They won't let me keep those keys.... <img src="/images/graemlins/frown.gif" alt="" />
Consequently, I'm forced to carry anything I want in the plane with me. This is a royal pain to me, because it limits how much I bring. My kit stays in my Flight Bag, which is on the backseat right behind me. If I have passengers, then I'll put it behind the rear seat in the baggage area. In a Piper Warrior (PA-28-151), this area is easily reached by those backseat passengers while keeping their belts on. If its on the seat behind me, I can reach my bag and kit without looking or turning around. In the event of an Emergency, like an engine out, I'll go for it after the plane is stopped, on the ground.

If it's going to be a ditching, I'm going to get the plane set up for my Best Glide Speed, then go for my life jacket. I'm always close enough to land that the Kit won't help me, plus it's not geared for water, with the exception of signalling stuff. I'd go for my Vertex Handheld Radio before I went for the kit over water. (waterproof Radio).

If I needed them to, I'd tell passengers to get it out and hand it to me.

If I had my own plane, then I'd keep the kit where it could be reached easily. Read as, not bolted down. Solo, it'd be next to me. With passengers, where they can reach it with belts on.

To stay with your idea of hypothermia, well, I'd get it out once I'd determined that engine wasn't restarting and take it with me.

Man, do I ever hope I never need that thing....

Happy Flying,
Kyle