It's a big hassle to apply for multiple-entry China visas at my local consulate.. letters required, multiple visits, long lines and so on (citizen of Canada). A colleague was bitten by a strange requirement- no double entry visas issued for first-time visitors. I don't have that problem- plenty of pages used up with visas.
Some agents in HK offer 12-month multiple-entry business China visas, and imply that they're available with rush next business day service, all for a fairly affordable price (maybe not for you hippietrail). They don't list invitation letters as among the requirements, nor any other kind of sponsorship.
Has anyone used a visa service in HK recently for a multiple-entry 12-month business visa, and if so was the service fast and did it require additional information beyond the completed application form, photos and passport? And if I fill it out for the information from my immediate visit, will that "intention" impact future visits that might be for longer?