Viz Reflective Canadian patch?
 

Does anyone have any idea -if it even exists, where to find a Canadian flag patch, similar to the mil issue ones, but reflective to visible light?

Looked around the net and couldn't find anything. I can probably DIY something, but if it already exists...

Have you tried construction safety supply stores? They have tons of reflective stuff, may quite possibly have Cdn flags, or atleast they might know where to get them.