It seems by default (at least on Ubuntu, but I think I saw the same on other distros) there are virtual TTYs 1-6 for text login, 7 for GUI login, and 8 upwards are unused or at least non-interactive (here they show only a blinking cursor). Is there a standard for which virtual TTYs should be used for what?
Up to whoever sets it up. Here on Fedora 18 (with
tty1 is graphical login, others are activated only if somebody tries to use them. What you describe is what the rough consensus was a year or two ago.