have there been any advancements in a SSO vbulletin system?

We are looking to expand our site into a smaller network of sites and one of the things we want to do is have individual sites but have a centralized user table so you have one login for all of the sites? I know there were hacks in the past but they all looked pretty daunting and dont work with the latest versions of vbulletin (from what Ive read).

Really hoping vbulletin would have offered this by now and done it right but it doesnt seem like it has been or is on any of the nearterm feature lists.