I think this is a bug or just perhaps I'm missing something but width and height always return same values regardless of orientation.

Sorry copied/paste incorrect. Should be as follows which are the correct args I assume. Still the height and width never update regardless of portrait or landscape on my phone.

See for yourself with debugging enabled - http://mobile.kci.com/parking

Using PR4 iOS 5

Code:
Ext.define('Sha.view.Main', {
    extend: 'Ext.Container',
    xtype: 'mainview',
    requires: ['Sha.view.MapContainer', 'Sha.view.MapSettingsContainer', 'Sha.view.MapResultsList', 'Sha.view.AboutContainer', 'Sha.view.ParkingResultsList', 'Sha.view.LotDirections'],
    config: {
        fullscreen: true,
        layout: {
            type: 'vbox',
            align: 'stretch'
        },
        items: [{
            xtype: 'image',
            height: 40,
            style: 'background-color:#1F1F1F',
            src: 'images/banner2.jpg'//,
            //flex: 0
        }, {
            xtype: 'tabpanel',
            activeItem: 0,
            tabBarPosition: 'bottom',
            flex: 1,
            items: [{
                xtype: 'mapcontainer',
                iconMask: true,
                iconCls: 'globe2',
                title: 'Map'
            }, {
                xtype: 'parkingresultslist',
                iconMask: true,
                iconCls: 'list',
                title: 'Parking'
            }, {
                xtype: 'mapsettings',
                iconMask: true,
                iconCls: 'settings',
                title: 'Settings'
            }, {
                xtype: 'aboutcontainer',
                iconMask: true,
                iconCls: 'info',
                title: 'Services'
            }, {
                xtype: 'lotdirections',
                iconMask: true,
                iconCls: 'compass3',
                title: 'Directions'
            }]
        }]
    },

    initialize: function () {
        //console.log('initialize viewport');
        this.callParent(arguments);
        Ext.Viewport.on('orientationchange', 'handleOrientationChange', this, { buffer: 50});
    },

    handleOrientationChange: function (t, o, w, h) {       
            console.log('calling layout');
            console.log(w);
            console.log(h);
            console.log('done call');
    }
});