Since vB4 is out, there are 2 new unfinished settings. At this moment those settings aren't used by vB4. I've asked in the bugtracker, but get no answer 'bout this.
I wrote my own solution to finish up those 2 settings and hope that this will be implemented in one of the next versions. I've attached a image to, see what I mean.

Ok, let's start (remember: this is a beta solution).

1st extend the database
ALTER TABLE `vb4_setting` CHANGE `datatype` `datatype` ENUM( 'free', 'number', 'boolean', 'bitfield', 'username', 'integer', 'posint', 'arrayinteger', 'arrayfree' ) CHARACTER SET utf8 COLLATE utf8_general_ci NOT NULL DEFAULT 'free'
2nd create two new GLOBAL phrases

title = datatype_arrayinteger
phrase = Array Integer
title = datatype_arrayfree
phrase = Array Free


The next parts is to change 3 files:
open admincp/options.php
search for:
case 'username':
$checked= array('username' => ' checked="checked"');
break;
add below:
case 'arrayinteger':
$checked= array('arrayinteger' => ' checked="checked"');
break;
case 'arrayfree':
$checked= array('arrayfree' => ' checked="checked"');
break;
search for:
<label for="rb_dt_username"><input type="radio" name="datatype" id="rb_dt_username" tabindex="1" value="username"' . $checked['username'] . ' />' . $vbphrase['datatype_username'] . '</label>
add below:
<label for="rb_dt_arrayinteger"><input type="radio" name="datatype" id="rb_dt_arrayinteger" tabindex="1" value="arrayinteger"' . $checked['arrayinteger'] . ' />' . $vbphrase['datatype_arrayinteger'] . '</label>
<label for="rb_dt_arrayfree"><input type="radio" name="datatype" id="rb_dt_arrayfree" tabindex="1" value="arrayfree"' . $checked['arrayfree'] . ' />' . $vbphrase['datatype_arrayfree'] . '</label>
search for:
if (is_demo_mode())
{
print_cp_message('This function is disabled within demo mode');
}

$db->query_write("
UPDATE " . TABLE_PREFIX . "setting SET
grouptitle = '" . $db->escape_string($vbulletin->GPC['grouptitle']) . "',
optioncode = '" . $db->escape_string($vbulletin->GPC['optioncode']) . "',
defaultvalue = '" . $db->escape_string($vbulletin->GPC['defaultvalue']) . "',
displayorder = " . $vbulletin->GPC['displayorder'] . ",

and change it into:
if (is_demo_mode())
{
print_cp_message('This function is disabled within demo mode');
}

if ($vbulletin->GPC['datatype'] == 'arrayinteger' OR $vbulletin->GPC['datatype'] == 'arrayfree')
{
$store = array ();
if (is_array (explode (',', $vbulletin->GPC['defaultvalue'])))
{
foreach (explode (',', $vbulletin->GPC['defaultvalue']) as $key => $val)
{
$store[] = $val;
}
}
$vbulletin->GPC['defaultvalue'] = serialize ($store);
$vbulletin->GPC['value'] = serialize ($store);
}

$db->query_write("
UPDATE " . TABLE_PREFIX . "setting SET
value = '" . $db->escape_string($vbulletin->GPC['value']) . "',
grouptitle = '" . $db->escape_string($vbulletin->GPC['grouptitle']) . "',
optioncode = '" . $db->escape_string($vbulletin->GPC['optioncode']) . "',
defaultvalue = '" . $db->escape_string($vbulletin->GPC['defaultvalue']) . "',
displayorder = " . $vbulletin->GPC['displayorder'] . ",

search for:
print_textarea_row($vbphrase['description'], 'description', $setting['description'], 4, '50" style="width:100%');
print_textarea_row($vbphrase['option_code'], 'optioncode', $setting['optioncode'], 4, '50" style="width:100%');
and add below:
if ($setting['datatype'] == 'arrayinteger' OR $setting['datatype'] == 'arrayfree')
{
$store = unserialize ($setting['defaultvalue']);
$setting['defaultvalue'] = (is_array ($store) ? implode (',', $store) : '');
}

next is to open includes/adminfunctions_options.php
search for:
// select:eval
case 'selectmulti:eval':
{
$options = null;

eval($setting['optiondata']);

if (is_array($options) AND !empty($options))
{
print_select_row($description, $name . '[]', $options, $setting['value'], false, 5, true);
}
else
{
print_input_row($description, $name, $setting['value']);
}
}
break;

and change it into:
// select:eval
case 'selectmulti:eval':
{
$options = null;

eval($setting['optiondata']);

if (is_array($options) AND !empty($options))
{
$setting['value'] = unserialize($setting['value']);
$setting['value'] = (is_array($setting['value']) ? $setting['value'] : array());
print_select_row($description, $name . '[]', $options, $setting['value'], false, 5, true);
}
else
{
print_input_row($description, $name, $setting['value']);
}
}
break;
search for:
case 'arrayinteger':
$key = array_keys($value);
$size = sizeOf($key);
for ($i = 0; $i < $size; $i++)
{
$value[$key[$i]] = intval($value[$key[$i]]);
}
break;

case 'arrayfree':
$key = array_keys($value);
$size = sizeOf($key);
for ($i = 0; $i < $size; $i++)
{
$value[$key[$i]] = trim($value[$key[$i]]);
}
break;
and change those lines into:
case 'arrayinteger':
if (!is_array ($value))
{
$value = unserialize($value);
$value = (is_array($value) ? $value : array());
}
$key = array_keys($value);
$size = sizeOf($key);
for ($i = 0; $i < $size; $i++)
{
$value[$key[$i]] = intval($value[$key[$i]]);
}
$value = serialize ($value);
break;

case 'arrayfree':
if (!is_array ($value))
{
$value = unserialize($value);
$value = (is_array($value) ? $value : array());
}
$key = array_keys($value);
$size = sizeOf($key);
for ($i = 0; $i < $size; $i++)
{
$value[$key[$i]] = trim($value[$key[$i]]);
}
$value = serialize ($value);
break;
next, open includes/adminfunctions_plugin.php
search for:
if (isset($vbulletin->options["$setting[varname]"]))
{
$newvalue = $vbulletin->options["$setting[varname]"];
}
else
{
$newvalue = $setting['defaultvalue'];
}

and add above:
if (trim ($setting['datatype']) == 'arrayinteger' OR trim ($setting['datatype']) == 'arrayfree')
{
$store = array ();
if (is_array (explode (',', trim ($setting['defaultvalue']))))
{
foreach (explode (',', trim ($setting['defaultvalue'])) AS $value)
{
$store[] = $value;
}
}
$setting['defaultvalue'] = serialize ($store);
}


Ok, with this changes you can have those settings working now.

How to use those options ?
In your product (under the settingsgroup) you can now have two more options:
This is example one:
<setting varname="multiinput_choose" displayorder="20">
<datatype>arrayfree</datatype>
<optioncode>multiinput</optioncode>
<defaultvalue>Hello up there,where on the air,it's hockey night tonight</defaultvalue>
</setting>

The optioncode is only multiinput and the datatype MUST be arrayfree or arrayinteger.

The next example is selectmulti:eval
<setting varname="multiselect_choose" displayorder="10">
<datatype>arrayinteger</datatype>
<optioncode>selectmulti:eval
$options = array (
'0' => 'you can choose what you want',
'1' => 'this is a multiselect field',
'2' => 'choose one or more',
'3' => 'option if you like',
'4' => 'this option wont work',
'5' => 'in a standard',
'6' => 'vBulletin 4.0.1',
); </optioncode>
<defaultvalue>1,3,4</defaultvalue>
</setting>
Here also you have to use arrayfree or arrayinteger. Others won't work !

I really hope, that those options are available in a further version of vB4.

Regards
Coroner