Proof of concept work for replacing WordPress' $menu variable with a class that implements ArrayAccess and Iterator.

WP_Deprecated_Menu_Array.php

<?php


class Array_Simulator implements ArrayAccess, Iterator {
  protected $menu;

  public function offsetUnset( $key ) {
    if ( $this->offsetExists( $key ) )
      unset( $this->menu[$key] );
  }

  public function offsetSet( $key, $value ) {
    if ( is_null( $key ) ) {
      $this->menu[] = $value;
    } else {
      $this->menu[$key] = $value;
    }
  }

  public function offsetGet( $key ) {
    if ( ! $this->offsetExists( $key ) )
      throw new Exception( sprintf( __( "Offset for ['%s'] doesn't exist on access.", 'sunrise' ), $key ) );
    return $this->menu[$key];
  }

  public function offsetExists( $key ) {
    return isset( $this->menu[$key] );
  }
  public function rewind() {
    reset( $this->menu );
 }

 public function current() {
    return current( $this->menu );
 }

 public function key() {
    return key( $this->menu );
 }

 public function next() {
    return next( $this->menu );
 }

 public function valid() {
    return false !== current( $this->menu );
 }
}

$menu = new Array_Simulator();
$menu[] = 'Test1';
$menu[] = 'Test2';
$menu[] = 'Test3';
$menu['foo'] = 'Bar';
header( 'Content-type: text/plain' );
print_r( $menu );

unset( $menu['foo'] );

foreach( $menu as $item ) {
  echo "\n{$item}";
}