In this thread (and, OH MY, there are a lot of them on mushrooms), stoot gave the idea +1 which hopefully means it is already on his radar and might be in motion.
I have been waiting to see pickable/growable/eatable mushrooms since the first day I played Glitch and saw all the awesome mushrooms all over Groddle Meadow and Forest!
It'd be cool to see another reason to move into a bog home. I'm all for mushrooms!
Maybe the more you let them grow the bigger they get, like real mushrooms Specifically Portobello mushrooms. But don't leave the enoki mushrooms out either.