Here is a little hack to emulate iOS 5 toggle in Sencha touch 2. I needed one for myself so hopefully someone will find this useful.

here is the js:
Code:
{xtype: 'togglefield',
label: 'iOS 5 Toggle',
cls: 'ios5_toggle',
listeners: {
    initialize: function () {
        
        var me = this;
        var mec = this.getComponent();
        var mythumb = this.element.down('.x-thumb');
        var mytoggle = this.element.down('.x-toggle');
        var myelement = this.element;
        
        mythumb.on({
            // this improves the ON/OFF effect 
            drag: {
                fn: function () {
                    var value,oldvalue,onCls,offCls;
                    value = me.getValue();
                    onCls = me.getMaxValueCls(),
                    offCls = me.getMinValueCls();
                    if(value != oldvalue) {
                        mytoggle.addCls(value ? onCls : offCls);
                        mytoggle.removeCls(value ? offCls : onCls);
                    }
                    oldvalue = value;
                }
            },
            // this improves the tap action (responds to tap on thumb)
            tap: {
                fn: function (e,t) {
                    var value,oldValue,onCls,offCls,thumb;
                    oldValue = me.getValue();
                    value = ((me.getValue()==1) ? 0 : 1);
                    mec.setIndexValue(0, value, mec.getAnimation());
                    onCls = me.getMaxValueCls(),
                    offCls = me.getMinValueCls();
                    mytoggle.addCls(value ? onCls : offCls);
                    mytoggle.removeCls(value ? offCls : onCls);
                }
            }
        });
        
    }, // initialize
} // listeners        
},
here is the css (put this somewhere AFTER the main css):
Code:
/* ------------------ *//* IOS5 TOGGLE
/* ------------------ */
.ios5_toggle .x-toggle {
    float:right;
    top:.45em;
    right:1.8em;
    border: 0.1em solid #888888;
    width: 4.7em;
    height:1.7em;
}


.ios5_toggle .x-thumb{
    width: 1.6em; /*adjust track*/
}


.ios5_toggle .x-thumb:before {
    width: 1.7em;
    height:1.7em;
    top:  -.06em;
    left: -.06em;
    
    
    box-shadow: inset 0 2px 1px white, inset 0 -2px 1px white ;
    background-color: #dfdfdf !important;    
    background-image: -webkit-gradient(linear, 0% 0%, 0% 100%,  from(#dfdfdf), to(#ffffff));
}


.ios5_toggle .x-toggle-on {
    background-color: #369aee;
     background-image: -webkit-gradient(linear, 0% 0%, 0% 100%,  from(#007fea), to(#6EAFE6));
     -webkit-box-shadow:  inset .4em .9em .1em 0 rgba(0,0,0,0.05), inset .1em .1em .3em 0 rgba(0,0,0,0.4);
    box-shadow: inset .4em .9em .1em 0 rgba(0,0,0,0.1), inset .1em .1em .3em 0 rgba(0,0,0,0.4);
}


.ios5_toggle .x-toggle-on:before {
    position:absolute;
    content:'ON';
    font-size: 1.0em;
    font-weight: bold;
    font-family: Arial, Helvetica, sans-serif;
    letter-spacing:-.05em;
    color: #fff;
    left: 1em;
    top: .28em;
}


.ios5_toggle .x-toggle-off {
    background-color: #fff !important;
    background-image: none;
    -webkit-box-shadow:  inset -.4em .9em .1em 0 rgba(0,0,0,0.05), inset -.1em .1em .3em 0 rgba(0,0,0,0.4);
    box-shadow: inset -.4em .9em .1em 0 rgba(0,0,0,0.1), inset -.1em .1em .3em 0 rgba(0,0,0,0.4);
}


.ios5_toggle .x-toggle-off:before {
    position:absolute;
    content:'OFF';
    font-size: 1.0em;
    font-weight: bold;
    font-family: Arial, Helvetica, sans-serif;
    letter-spacing:-.05em;
    color: #999;
    left: 2em;
    top: .28em;
}
here is the screenshot:
ios5toggle.png