I went back to Beijing last May and I am on my eight-year of H1-B visa. I did not have any problem getting the visa in Beijing except the visa officer(vice general consulor) said he and other people had never seen anyone with h-1 over 6 years. I showed him my h-1 petition where a very brief explanation on the validity of extending h-1 beyond 6 years. He gave me the receipt for pick up the visa though he told that they will do some research and asked if my attorney could help them clearify this, but if nothing goes wrong, I shall be able to pick up the visa in 2(or 3 days), just like anyone else who has been granted a visa. I did ask my attorney to fax some legal explanation to Beijing embassy. So just prepare to show them the legal basis of extending h-1B visa beyond 6 years. Good luck!