Anyone have some advice on the best way to go about getting a foreign visa when you don't live anywhere near a consulate?

I'm going to China this fall, and obviously need a visa. But... they don't accept mail-in applications. Someone has to go to the consulate, in person, and apply. Now, I *can* hire an intermediary. But my request to the Chinese consolate to recommend authorized intermediaries got me a "No, you have to find one on your own" response.

There are any number of places that advertise visa-procurement services online. But I'm a little bit wary of signing up and *mailing my passport* to someplace that I've just found online. Anyone ever used one of these services? The one I'm seeing most often is