We're about to start delivering some training courses to paying clients via online multimedia and are looking for the best delivery platform for our needs. Currently we're looking at Screencast as a suitable service provider but although there are a lot of things I like about the service they don't provide much functionality or granularity in the way of limiting access to content (for example there's no easy way of revoking access to content after a specific time period).

Does anyone have any experience of a similar situation and feel able to recommend alternatives (either here or via PM)? Many thanks in advance!