David,
Like Willie said they are from ALIEN. I believe Kane and Ash wore the UK triangle and the rest of the crew wore the Tri-Centennial patch.
As far as us Canucks are concerned (according to the technical manual) by the time of "Aliens"- North America, Central and South America have joined together to form the United Americas.
Guess if you wanted to reproduce a Canadian patch for the ALIEN timeframe, you could go with the red mapleleaf in the center with three red stripes rotating outwards.
-Kevin
"
Marines I see as two breeds, Rottweilers or Dobermans, because Marines come in two varieties, big and mean, or skinny and mean. They've got really short hair and they always go for the throat."