Yup, there is at least one major third-party one, though (Jasmine), which complies with the API requirements that Microsoft is apparently not willing to deal with (presentation of the actual video via HTML5, etc.)
Does Google abide by its own API usage restrictions? It might seem like a trite point, but it's important given that it publishes for the two dominant platforms. It'd be an easy way to edge out competing applications restricted to a less feature-rich toolset.