Add ability for ActionItem to have a custom view associated with it, instead of using predefined icon/text. For example something like:

<ActionBar title="Something">
  <ActionBar.actionItems>
    <ActionItem ios.position="right" tap="doneTap">
        <ActionItem.actionView>
            <StackLayout>
                <Label text="Label1" backgroundColor="red"/>
                <Label text="Label2" backgroundColor="green"/>
            </StackLayout>
        </ActionItem.actionView>
    </ActionItem>
  </ActionBar.actionItems>
</ActionBar>

Implementation suggestion:
For iOS - use - (id)initWithCustomView:(UIView *)customView of the UIBarButtonItem. The catch is that in order to be able to handle tap the custom view must be a button. So the custom view must be added as a sub view to a UIButton. And then the UIButton should be passed to the initWithCustomView method.

For Android - use setActionView of MenuItem http://developer.android.com/reference/android/view/MenuItem.html#setActionView(android.view.View)