I only have the one example right now, but anyone else can feel free to post their examples here.
The frost is kinda hard to see in the beginning of this video, since it was mostly melted. For anyone who doesn't want to watch it, it ends with the volunteer tomato seedlings about twenty or thirty feet away. They're technically inside, but there's no south wall so... microclimate.
It's not as cool as a lemon tree in Montana, but pretty cool for a happy accident.