From the founder of Ubuntu project: Now we’re thinking of having a "user and business" conference, aimed at bringing together the people who deploy and manage Ubuntu in the real world (well, in the USA in particular, but let’s think globally) with those who help to produce it. The big question is - who would want to come?
In order to run such an event we would need about 500 people to attend. It would be a 2-day conference (with additional days of workshops and tutorials separately, probably) and would likely be run in close proximity to another big event. The cost per delegate would be around $700. We’d bring together companies offering services based on Ubuntu, developers and ISV’s building solutions on it, and end users who just want to squeeze the most out of it. It would be a traditional style conference, with tracks and keynotes etc.
http://www.markshuttleworth.com/archives/61