By chance I went to the main ETS page today and found the answer to my window punch/whistle problem there.

Doug has recently posted a story about 3 college students who perished when trapped inside a submerged car.

Shown was a resque tool called the Houdini Automotive Escape Tool which combines a window punch, seatbelt cutter, whistle and LED flashlight all in one small unit, sounds just like what I was looking for.

Now I just have to find a source in Canada.

Mike