[OpenID] suggested server for private SSO using openid?

[SitG Admin]

>I thought our requirements were simple but I am having trouble finding a
>solution that fits.

It looks like OpenID will work okay for what you've described. A 
"single" personal identity server can actually handle multiple 
identities (in fact, it's rare to find code for a "Provider" that 
*isn't* designed for multiple users), and there are libraries in 
place for a number of programming languages. I recommend looking at 
openidenabled.com for PHP.

-Shade