Question

I mean to create new array with identical keys but every value as specified in second parameter.

Just like you have array_fill_keys

 array array_fill_keys ( array $keys , mixed $value )

Where $keys would be a multidimensional array

Answer 1

Not that i know of but you can try

$array = array("A","B");
$array["C"] = array("X","Y");
$array["C"]['Z'] = array(1,2,3);

var_dump(fillKeys($array, "banana"));

function fillKeys($keys, $value) {
    $return = array();
    foreach ( $keys as $key => $val ) {
        $return[is_array($val) ? $key : $val] = is_array($val) ? fillKeys($val, $value) : $value;
    }
    return $return;
}

Output

array (size=3)
  'A' => string 'banana' (length=6)
  'B' => string 'banana' (length=6)
  'C' => 
    array (size=3)
      'X' => string 'banana' (length=6)
      'Y' => string 'banana' (length=6)
      'Z' => 
        array (size=3)
          1 => string 'banana' (length=6)
          2 => string 'banana' (length=6)
          3 => string 'banana' (length=6)