I'm a rather paranoid guy, so I like to set a really long password. Although I re-use my passwords a lot, I have four from 8 alphanumerical characters to 28 alphanumerical characters, the longest one is for crucial things like login password and other stuff... and I wanted to make my root password the 28 character one, but apparently it has problems with that. Is there a way to force a longer password, and if so, what difficulties could arise while doing so? Although having to type the ridiculously long password whenever I type in sudo, and since logging in as root is a no-no on Ubuntu, it's going to be very often, but I'd rather have to take extra time than have someone break into my laptop (Yes, I'm paranoid) and doing what he wants to it, and of course threats via online/hackers and whatnot. I am aware the possibilities of that happening are rather slim, but I like to be prepared.

Anyway: Clarification -- Limits to 8 characters, when I try to set longer, it truncates it to the first eight characters and anything past that becomes invalid. I want to set at least a 10 character password, but ideally I want a 28 character password.

http://www.deer-run.com/~hal/sysadmin/pam_cracklib.html Cracklib PAM module seems to be one way to enforce or change the minimum password length. Perhaps 8 characters is already set there.

Have a look to see if you have a file /etc/login.defs. The 8 char limit is due to using the old Unix crypt function.
These days various hash fns are available for much longer passwd eg on RHEL 6.3, default setting is
See note here http://linux.die.net/man/8/pam_passwdqc for max