Jan Štětina

Warning: This plugin is currently broken (at least for some sites) and I have no time to maintain it. I plan to solve all the issues from the support forum but I have no idea when that might happen (perhaps summer 2014). I am sorry and thank you for the understanding.
Provides a system for registration requests and their processing in multisite.
Blog administrator can place a shortcode <code>[murm-form]</code> on their blog, which will display a registration form. Visitors can then use this form to request registration. Such a request must be first moderated by the blog admin. If it is accepted, it’s passed on to the blog superadmin, who also has to approve it in order to pass. After approval the plugin creates given user accounts with subscriber rigths on the blog from which it was requested and sends login information to the user.
Per-blog settings
<ul>
<li>can be deactivated</li>
<li>notification via nag or e-mail on new requests</li>
<li>antispam (needs Akismet API key)</li>
<li>requests on the blog admin level can be automatically approved</li>
</ul>
Per-site settings
<ul>
<li>optional e-mail notifications</li>
<li>custom e-mail templates</li>
<li>blog administrators can be allowed to delete a request without notifying it’s author</li>
<li>requests on the network admin level can be automatically approved (this means that only blog administrators decide about their requests, if no error occures)</li>
</ul>
This plugin was developed for a small blog server (cca 30 blogs), so that superadmin would have control of newly created accounts (because some people were confused and got themselves unneccessary multiple user accounts).
Makes use of the <a href="https://wordpress.org/extend/plugins/wordpress-logging-service/" rel="ugc">WordPress Logging Service</a>.
In future there will be more options to modify default plugin behaviour.
<h3>Wishlist</h3>
Below are listed requests I know about and I’m going to process… eventually. Please be VERY patient.
<ul>
<li>“I have a request of asking for password on registration form. That way the user can pick out a password and have it automatically populated in the site user data.”</li>
<li>sidebar registration widget</li>
<li>attach custom admin message to user on request approval/denial</li>
<li>correct i18n, custom blog admin messages</li>
<li>custom shortcode css (error/ok) + information</li>
<li>save all settings as a single wp option</li>
<li>combine with pure-murm?</li>
<li>“I would like to add more fields like “country” in the Registration Page.”</li>
<li>custom new user default role</li>
<li>recaptcha on registration</li>
</ul>

Multisite User Registration Manager

Worked for me

Provides a system for registration requests and their processing in multisite. Two-level moderation.

HuangYe WuDeng

Features: Adds remote attachments support for your WordPress blog.
use this plugin, you can upload any files to remote ftp servers(be aware that your FTP server must has Apache or other HTTP server daemon) in WordPress.
<ul>
<li>Support both single user site AND multisite.</li>
<li>support upload files to remote FTP server.</li>
<li>support delete files on remote FTP server.</li>
<li>works just like the files are saved on your local server-_-.</li>
<li>with this plugin,you can move all your local server files to remote server.</li>
<li>after you’ve uninstall this plugin,you can move remote server files to local server if you’d like to do so.</li>
</ul>
For MORE information,please visit the <a href="http://80x86.io/?p=5001" title="plugin homepage" rel="nofollow ugc">plugin homepage</a> for any questions about the plugin.
<a href="http://80x86.io/?p=4993" title="installation guide" rel="nofollow ugc">installation guide</a>
<ul>
<li>version 1.3.1 fixup thumbnail srcset url with WP 4.5+</li>
<li>version 1.3.0 edit or crop image is working correctly now.</li>
<li>version 1.2.1 fixed the bug when uploading new theme or plugin this plugin may cause it to fail.</li>
<li>version 1.2.0 added duplicated file checking,so that the existed remote files will not be overwrote.</li>
<li>
version 1.1.0 added compatibility with watermark plugins
</li>
<li>
1.0.2 增加自动创建远程目录功能。解决在某些FTP服务器出现“在远程服务器创建目录失败”的问题。
</li>
<li>1.1.0 增加与水印插件的兼容性，使上传到远程服务器的图片同样可以加上水印</li>
<li>1.2.0 增加重复文件检测，避免同名文件被覆盖。更新和完善了帮助信息。</li>
<li>1.2.1 修正在后台上传主题或插件时的bug.</li>
<li>1.2.3 加密保存FTP密码,增加插件兼容性（同时支持ftp扩展方式和socket方式连接远程FTP服务器）</li>
<li>1.2.4 增加重复缩略图字段检测</li>
<li>1.2.6 增加对xmlrpc支持(支持通过Windows Live Writer 上传图片时自动上传到远程ftp服务器)</li>
<li>1.2.7 修复Windows Live Writer 上传图片时url不正确的bug</li>
<li>1.2.8 修复在PHP 5.3.x以后版本中报“Fatal error: Call-time pass-by-reference has been removed in hacklogra.class.php on line 539”错误的兼容性bug.</li>
<li>1.3.0 修改图片后已经可以正常重新回传至远程ftp服务器了。</li>
</ul>
更多信息请访问<a href="http://80x86.io/?p=5001" title="plugin homepage" rel="nofollow ugc">插件主页</a> 获取关于插件的更多信息，使用技巧等. 
<a href="http://80x86.io/?p=4993" title="安装指导" rel="nofollow ugc">安装指导</a>

Hacklog Remote Attachment

Adds remote attachments support for your WordPress blog.

Multisite User Registration Manager vs Hacklog Remote Attachment