In the Thunderbird distance programs, we emphasize what we call 'lecturettes'. These are short (15 minute) lecture videos on specific topics. They force the professor to really focus on content, and leave out information that doesn't directly relate. Stories, examples and additional information can be put into a 'conversation' in the class discussion forums.
This article in Smart Classroom, Teaching in One Minute Snippets, talks about 60 second 'micro lectures', and might be an option for those faculty that have content that needs to be updated regularly. A short lecture is by it's nature easier to update with new data, and would take much less time than re-recording an 30 minute video. It's worth a look!