I've ported the yahoo history browser to ext. Many of the changes were culled from various forum posts (eg, getting rid of document.writes), and I removed the yahoo dependency so it now works with any ext adapter. Is this useful to anyone? I can uploaded it to the ux area in the wiki if anyone thinks it's worthwhile.
Documentation is from yahoo: http://developer.yahoo.com/yui/history/
Just replace every YAHOO.util.History with Ext.ux.History.