Regarding Kim's question about streaming vendor lists, Scott Spicer (U of MN) put together a good list on ALA Connect (http://connect.ala.org/node/183711), though it is not entirely complete (e.g. Media Education Foundation and New Day are missing). The list can be updated by any registered user, so maybe it can work as a community focal point?
As to Jo Ann's lament about the absence of one database to rule them all -- it's a great idea. In a less grand way it was also one of the ideas behind Bullfrog Films and Icarus Films working together to set up Docuseek2, which also includes films from Terra Nova Films and now Kartemquin Films too. Not exactly exhaustive, but we set it up as a big tent for the founders and other distribs and independent producers in the academic social issue / documentary space. Jim Davis Docuseek2 VIDEOLIB is intended to encourage the broad and lively discussion of issues relating to the selection, evaluation, acquisition,bibliographic control, preservation, and use of current and evolving video formats in libraries and related institutions. It is hoped that the list will serve as an effective working tool for video librarians, as well as a channel of communication between libraries,educational institutions, and video producers and distributors.