If you care to give it a try sometime in the future, in a nutshell, this is what you do ...
1. Make sure you are using the new version, since that has a master switch in the config.php

2. In your site url, put 8thos.com
3. In the blogs url, put 8thos.com
4. In the cookies domain, put .8thos.com
5. You need to create an A entry on your DNS for *
Code:
*.8thos.com. IN A 173.248.188.141
6. You need to modify your apache config to make the default DocumentRoot your XenForo installation
7. Enable the setting in the config.php (the name of the setting is on the Blog Multisite options)
Done