If all you're really hoping to do is tinker so that you get an auto-login terminal on startup, then you have lots of options. Some login managers have automatic login settings--where a specific user is logged into the system after a specific time expires with no other login request.
Alternatively, since you mention "batch files" in an earlier post, perhaps you're thinking in terms of system startup scripts. If that's the case, then I'd point you to read about the inittab file (man inittab
and various websites you can find with Google). It should not be difficult to modify inittab to startup a terminal on one of the virtual consoles (Ctrl-Alt-FX) under a specific user id (e.g. "su -c '/bin/bash' someusername").
If you're interested in what I described earlier (a terminal displayed simultaneously with the username/password request), then I can't help you there--I've never tried it and can only guess where to start (i.e. the login manager's configuration file and/or source code itself).
but the answer to the question WOULD provide a means of circumventing the login
I understand the concern, and we could have a robust discussion on it. Though, from my perspective, there's no more danger than when a computer offers a service to the outside world. The service could be (a) full of security exploits or (b) mis-configured allowing (potentially unintended) user-elevation. The same is true with an auto-login terminal. It can be configured/locked-down well or not.
The point of difference appears to be that you're thinking of it as the OP asking for a method to open a terminal on a system that is not configured to provide it. Whereas my perspective on it is giving direction to a solution that requires pre-existing administrative access to provide the terminal. If the OP has administrative access, there's no security problem. If the OP does not have administrative access, then he has no ability to configure the system and the point is moot.
But, if one of the wise and powerful forum mods comes along and passes judgment that this, indeed, runs afoul of LQ policy. Then so be it.