Disclaimer: I work for Oracle but not in sales nor in any branch related to this product.
At the office (where I work as a senior iOS / OS X native app developer), we have Oracle SSO running on all of our internally-deployed apps, including web sites, desktop apps, mobile.
OP talks of holy grail of IT so, while I dont know of alternatives, based on my experience, it's quite possible to have a decent single sign-on system.
Obviously, Oracle's offering is not free (as in beer speech) at 85$ a seat. It's best to contact the sales rep to see if any bulk or student pricing apply (I do not know as I'm not in sales).