This same item was addressed in Popular Science (or Mechanics) about 20 years ago. It was based on a foul weather coat and contained a plethora of survival equipment. To the best of my memory it had a single person raft, EPIRB, flares, smoke, signal mirror, etc as well as rations and (I think) a small hand powered desalinator or solar still. The vest had either built in floatation or an inflatable system.

On the subject though, what would you want on your person if you go over? Start of a (too inclusive) list below. What would be the bare min? Feel free to add or subtract.

Flares
Whistle
Mirror
Smoke
Dye
Water activated PLB or EPIRB
Strobe
Flashlight
Tether with carabiner
Drouge
Rescue knife

This is heavy on the signal end to support rescue. How to combat hypothermia, dehydration?