[eluser]sszynrae[/eluser]
you could probably do a periodical updater ajax request thing to check if you are logged in, and if that fails just present the login form overlayed or something.
as for the redirect, that can be done easily with javascript. make an input field near your hidden login form (if you use a greyout screen or another hidden login form type approach) and login via an ajax request. onsuccess do something like this: (I use prototype, but you get the gist)
i observe each link that require login initially and onclick stop the event, put the event.element().readAttribute('href') inside the hidden input. the actual login link itself doesnt actually lead anywhere (hence refresh (else part))
edit: removed = wind0w.loc4tion (made it code safe now) : P
