Peter Kellner and Ed Spencer present at a local meetup in Silicon Valley: meetup.com/The-San-Francisco-ExtJS-Meetup-Group/events/28760211/
Peter introduces MVC and demonstrates an application he has created with these principles.
Ed shows how to use Ext JS 4's new features to create well-structured applications - and then answers a whole range of questions relating to Sencha and its framework technologies.
You can see Ed's slides at slideshare.net/edspencer/ext-js-4-mvc
[NB a small section of Peter's presentation was not recorded correctly. Also apologies for the sound quality - the meetup was in an open-plan area]