Your problem at that point is getting the customers to you. I'd be willing to bet that not many people would be willing to pay for it before they have tried and failed at the consulate. And at that point, they are going to stumble on that van before they see your website.
That's an interesting take - there's always the danger that filling in the gaps in someone else's product will cause that someone else to wake up and fill it in for you.
Seeing as this is a government failing, however, makes me think that it'll be a long time before they decide to improve enough to make these guys unnecessary.
There are tons of businesses providing this service (search for "Chinese visa"), including picking up and dropping off relevant documents, so clearly there's a market for it before trying and failing. However it is also a lot more competitive market, so there'd still be a problem getting the customers to you.
