In a general way, ACLs could be accessed from anywhere. A simple way to do it is :
1) Store it in your registry : Zend_Registry::set('acl', $myACLObject);
2) Get it when you want : Zend_Registry::get('acl');
For your specific problem, layout has access to each view variables you declared in the controller :
1) Declare your variable in the controller : $this->view->myVarACL = $myACLObject;
2) And in the layout, you can do this : var_dump($this->myVarACL);