Limit the available plugins and themes for networks sites in a WordPress multisite install using Paid Memberships Pro.

pmpro-limit-available-plugins-and-themes.php

<?php
/*
Plugin Name: PMPro Limit Available Plugins and Themes
Plugin URI: http://www.paidmembershipspro.com/wp/pmpro-limit-available-plugins/
Description: Limits Which Plugins are Available for Network Sites
Version: .1
Author: Stranger Studios
Author URI: http://www.strangerstudios.com

	1. Place this file in wp-content/mu-plugins.
	2. Update the pmpro_plugins_per_level and pmpro_themes_per_levels globals in the plugin.
	3. Make sure that you have "Enable administration menus" checked in the Network Settings page of the network dashboard.
*/

/*
	This is the array to store which plugins are available for which level
	
	Level 1 members have access to akisment and hello dolly.
	Level 2 members have access to just hello dolly.
	
	Make sure that the plugin entry in each array is the actual path and file name of the plugin on your server
*/
global $pmpro_plugins_per_level;
$pmpro_plugins_per_level = array(
	1 => array(
		'akismet/akismet.php',
		'hello.php'
	),
	2 => array(
		'hello.php'
	)
);

/*
	This is the array to store which themes are available for which level
	
	Level 1 members have access to twenetytwelve, twentyeleven and twentyten.
	Level 2 members have access to twentytwelve and twentyten.
	
	Make sure that the level entry in each array is the directory name of the theme
*/
global $pmpro_themes_per_level;
$pmpro_themes_per_level = array(
	1 => array(		
		'twentyeleven',
		'twentytwelve'
	),
	2 => array(
		'twentytwelve',
		'twentyten'
	)
);

/*
	Limit the listed plugins is the admin
*/
function pmpro_limit_available_plugins($plugins)
{	
	//don't filter network admins
	if(!current_user_can("manage_network_plugins"))
	{		
		global $pmpro_plugins_per_level;
		
		$membership_id = plap_getMembershipId();
				
		//filter by membership level
		if(!empty($pmpro_plugins_per_level[$membership_id]))
		{		
			$available_plugins = $pmpro_plugins_per_level[$membership_id];		
			$newplugins = array();
			foreach($plugins as $plugin => $data)
			{
				if(in_array($plugin, $available_plugins))
					$newplugins[$plugin] = $data;	//add it
			}
			
			$plugins = $newplugins;
			return $plugins;
		}
		else
		{
			//plugins weren't specified for the users membership (or he has none) so return no plugins
			return array();
		}		
	}
		
	return $plugins;
}
add_filter("all_plugins", "pmpro_limit_available_plugins");

/*
	Limit the listed themes is the admin
*/
function pmpro_limit_available_themes($themes)
{		
	//don't filter network admins
	if(!current_user_can("manage_network_themes"))
	{		
		global $pmpro_themes_per_level;
		
		$membership_id = plap_getMembershipId();
				
		//filter by membership level
		if(!empty($pmpro_themes_per_level[$membership_id]))
		{		
			$available_themes = $pmpro_themes_per_level[$membership_id];		
			
			$newthemes = array();
			foreach($themes as $theme => $data)
			{			
				if(in_array($theme, $available_themes))
					$newthemes[$theme] = $data;	//add it
			}
			
			$themes = $newthemes;
			return $themes;
		}
		else
		{
			//themes weren't specified for the users membership (or he has none) so return no themes
			return array();
		}		
	}
		
	return $themes;
}
add_filter("allowed_themes", "pmpro_limit_available_themes");

/*
	Get the membership id of the current user at the main site level
*/
function plap_getMembershipId()
{	
	global $wpdb, $current_user;
	$prefix = str_replace($wpdb->blogid . "_", "", $wpdb->prefix);		
	$membership_id = $wpdb->get_var("SELECT membership_id FROM " . $prefix . "pmpro_memberships_users WHERE user_id = '" . $current_user->ID . "' AND status = 'active' ORDER BY id DESC");
	
	return $membership_id;
}