Any way to make jQuery.inArray() case insensitive?

In case anyone wanted a more integrated approach using jquery:

(function($){
    $.extend({
        // Case insensative $.inArray (http://api.jquery.com/jquery.inarray/)
        // $.inArrayIn(value, array [, fromIndex])
        //  value (type: String)
        //    The value to search for
        //  array (type: Array)
        //    An array through which to search.
        //  fromIndex (type: Number)
        //    The index of the array at which to begin the search.
        //    The default is 0, which will search the whole array.
        inArrayIn: function(elem, arr, i){
            // not looking for a string anyways, use default method
            if (typeof elem !== 'string'){
                return $.inArray.apply(this, arguments);
            }
            // confirm array is populated
            if (arr){
                var len = arr.length;
                    i = i ? (i < 0 ? Math.max(0, len + i) : i) : 0;
                elem = elem.toLowerCase();
                for (; i < len; i++){
                    if (i in arr && arr[i].toLowerCase() == elem){
                        return i;
                    }
                }
            }
            // stick with inArray/indexOf and return -1 on no match
            return -1;
        }
    });
})(jQuery);