Some more work at AppFoundation: http://www.appfoundation.com/?p=453
Ultimately all of this is interacting with the HTML model so as long as you can translate into that you are able to almost anything. There were problems with this in terms of research because of the difference in how iFrames are handled in the various versions of Ext JS. In an earlier version there was even an iFrame component. While there are several components available for other versions of Ext JS, I couldn't get them working in the exact manner in which I wanted so I ended up just taking the simple approach. The simple approach being just putting the HTML tag for an iFrame in a panel.
See the link for the code.