So I have thrown the Idea back and forth, and after deciding I wasn't going to do any work on Open ID for Orchard, I have changed my mind! So I have set up a new codeplex project called orchardopenauth (http://orchardopenauth.codeplex.com/).
The first goal is to get an extensible Open ID implementation working inside of Orchard without having to change any of the Orchard base code.
Why OpenAuth? Why NOT OpenID?
Open ID is small part to a very large piece of the puzzle. I want this module to be more than just about Open ID, eventually I see a full implementation of the DotNetOpenAuth project within the Orchard Framework, though these are early days and I have only just started.
Any ideas!.. or feedback, please let me know!