Rails partial inheritance hack
This actually looks pretty solid.

Another approach would be to sub-class the Renderer and make it responsible for retrieving the base classes' to_partial_path.

For me this feels a bit cleaner because it is sub-classing versus monkey-patching and because the renderer is supposed to find and load the template anyway while the model class shouldn't case about the (non-)existence of the view at all.

After looking at it for a while, I would the make sub-classes partial_path check if the template exists and find the template of the base class if it doesn't.