Yes, I've sometimes seen this. This form of bioluminescence is most commonly known as foxfire, and is (as you describe) usually found in mushrooms  growing on rotting wood. (Especially the delicious "Honey Mushroom", Armillaria/Armillariella Mellea! ).

Here's a few web links with more info

(You need to Login or Register to view media files and links)
(You need to Login or Register to view media files and links)
(You need to Login or Register to view media files and links)

I don't have much mushroom-picking experience in Ontario, mostly chanterelles, lactarius, boletus. Any other amateur mycologists out there?

Slime Mold was the first thing that hit my brain.  I used to have one as a pet.  Part animal/part plant.  You decide.  Google it.

Here's a link
(You need to Login or Register to view media files and links)

While Kingfisher & I were camped in Quetico, we happened to notice a faint blue-green light in several places on the ground. Upon further inspection we discovered the light was coming from some decaying wood on the ground.

I'm assuming this was some kind of bioluminescent fungus that caused this. Has anyone ever seen this before? Does anyone know what we may have actually seen?

Thanks