Canoe pontoons?

Has anyone done it? I did the obligatory google search, and found nothing
in 20 seconds (so it must not exist, right? ;-) Obviously, though, I'm not
the first idiot to think of it.

I'd like to see a light plane with canoes for pontoons. There'd be vertical
tubes that would drop down (think a pickup truck camper's vertical supports
for when you don't have the pickup under it), so you could taxi to shore,
jack down the tubes (broad plates on the bottoms for mud?), and detach the
canoes. Go fishing for the day, then re-attach the canoes, jack up the
tubes and take off.

Am I nuts? I suppose someone's going to tell me that it'd be easier to
convert a pontoon to something that could double as an inefficient canoe.
;-D

The big hazard is an obvious one, but what the heck. There's gotta be a
way.

- Scott