Manitoulin Island is littered with wild apple trees. The more I learn to identify apple trees, the more I see scattered all over the landscape. Unfortunately they are all located on posted private property, so even investigating them is illegal without the express permission of landowners.
Next time I'm there during hunting season, I will try to track down some landowners and see if I can get scion wood and seeds. Most of the ones I have access to tend to start dropping the last week of September, which is fine for archery season, but by the time rifle week rolls around, there's not much left. I would love to find some cold hardy late hangers up there just for the sake of variety.