The waterproof bags work FINE for what is in my EDC pack - and yeah, everything is backed up there. I'm NOT worrying about what's in my pack

As for the otterbox and pelican boxes. Those I know about, but as you said, a BIT too large for "shirt pocket carry".

What is really needed is a box that can be SLIGHTLY bigger than an altoids tin, but waterproof.

I've bever actually seen one of the old Military "decon" kit cases - I've heard they MIGHT me around the correct size...