I'm trying to get a script to open a gnome-terminal and input commands into it, just as you would typing them in. That way, I can automate commands using bash, even if the terminal is running a non-bash program like telnet, mysql, vim, etc.

So, for instance..

I would like to open telnet to connect to a mud (I'm aware of the security concerns) and input commands through a script.

This way, I can log in, enter name/password, and do some start-game stuff automatically.

This isn't just for a mud, though. I'd like to be able to script inputs for any terminal application... maybe automate vim, mysql, or whatever.

Have you looked into expect scripts? Whereas I have not tried using them to start a terminal session, I have use it to automate interactive installs.