Technically, the original node must have been obtained from a parent at some point, but I can easily dream up a scenario where you would be handed a node ID without knowing where it came from. For example, you might want to know the project setings of a given clip node you were asked to encode.
Unfortunately, the answer is stil the same for now. The only possible workaround (a really bad one) is to traverse the entire node hierarchy until you find your node ID.
Perhaps you can elaborate a bit on the details of the problem you're trying to solve so that I can provide more constructive answers... 🙂
Thanks,
Dan