As it turns out, a number of SQL presentations (both at conferences and even free events) are based on white papers or articles the speaker has previously written. Certainly not every one of them, but definitely the case for the top speakers.
My top community presentations and webcasts are based on articles I've written in the past, and I'll provide a link to the attendees if they want to read the original article. I usually joke and use a musician analogy - the article is the studio version of the song and the presentation is the live version with some extras built in. :)
Again, I think you'd benefit from studying some of the key people in the SQL community to see what they are doing.
A question - have you produced webcasts before? They require as much forethought and preparation as a paper. Given the visual nature of certain aspects of certain tools, they are invaluable.