Firstly, you want to be very careful when it comes to uing a visa agent. Just because you have not heard anyhting bad, wel, this could simply mean they are new, or have changed their name, or not screwed over enough people to have word out on them.

Firstly, don't trust anyone who has a simple yahoo, or hotmail account. Reputable agents, if there is such a thing, since it is a pretty shady area to begin with, will have a website, and a website email address. They won't be asking you to email tham at yahoo or gmail, believe me.

As for visa agents in Shanghai, none of them that I know of will let you get a visa done outside of Shanghai. You either must live there or travel there, I kno thos from research and first hand experience. Beijing agents are a bit different, and you can mail them your passport at the least. Most other places require you to be the physically. depending on locale.

Be careful though, any fool who sends their passport to someone ho doesn't have a website of quality or a private email is just asking to get the passport stolen. Many a person has sent their passport to someone they thought was a reputable visa agent, *cough cough* only to never see it again, or hear from the agent again.

References can be helpful, however be careful, often agents will just give you email accounts they own, and will write themselves a glowing report. Use someone only a friend has used, or that you can verify through research it legit. Otherwise, don't trust "not having heard anything bad" as a good reason to use them.

Finally the OP told me via email that he knows many reputable visa agents in mainland China. This prompted me to ask, and ask again, what the heck did you bother us with your questions for if you already have what you say you seek? Very dumb if you ask me. If you know reputable agents, they would have told you what I told you in my resopnse, which I posted here. Clearly they are either not reputable, or not very good at their jobs. I'd suggest finding another agent, or agents, but don't waste our time if you are not going to use our advice, and continue to use the same crap agents, who know less than I do. I'm thinking they should know more since it is their livelihood, but hey, maybe that's just me. Bye.