This is an interesting topic, and it all looks pretty good so far. Couple of points / questions.
I agree with the sentiments of Jezz to be honest, as regards the log in screen being of a more generic nature. To me, any individualness (lol, as if thats a word!) should only begin once a user has logged in and every user should be faced with the same log in screen.
That said, I was wondering if it is possible to have the login screen with a duplicate of the splash, simply with text over laying. The effect I am trying to acheive is that on boot, a splash comes up, couple of seconds and then it appears that the login text fades in.
Hope that makes sense and is possible, as I would say this would maybe would solve the dilemma of what graphics to have for the log in, instead of trying to match the skin, match the splash, and then the intro sequence starts to work together.
So here is a quick mock up to show what i mean, only a quick job but u get the idea...