Ability to login to VB when commenting on Wordpress?

[Clutch]

I posted this on VB.com and from the admin response, it didn't look like there was any solution out there, but I was directed to VB.org.

I'm running VB 3.8.6 for my forums and Wordpress for a separate blog site. I have looked into the vbulletin.org mod for a Wordpress-VBulletin bridge and I'm not sure that is the route I will go. My blog and forum are on the same server but different subdomains and I don't necessarily need users to login to the forum and stay logged in on the blog.

I'm mainly just looking for a way for users to have the option to comment on the Wordpress blog with their VB forum account (forum username/password). It would be great if users had the option to comment via Facebook, Twitter and/or anonymously. I thought I found the ideal solution with Echo (http://www.aboutecho.com/):

Engage your community in this powerful, configurable and extensible conversation platform. Enable users to log in and share with their choice of social network and/or your own proprietary login. Spam and bad word filtering, advanced moderation tools and more. Increase engagement, time spent. Real-time commenting also pulls in tweets about your content when someone mentions it on Twitter so you can get more of the conversation.

... but unfortunately it comes with a monthly charge that is expensive. Ideal solution is something like IntenseDebate/Disqus with the option to login using your VB account. I've been doing a lot of searching and research but I'm hitting dead ends and am considering scrapping the hope and just going with Facebook comments, Disqus or IntenseDebate.

Anyone know of a solution like that? Thanks for your help.