Almost since the start, I have wanted a mechanism to start a terminal session but not put a window on the screen. That is, start a terminal process in the dock. In my case I collect email via pop3 from a remote source and use ssh tunnelling to connect to the pop3 service via an encrypted connection (also incorporatng ssh-agent, but that is another story). So far I've just started a new terminal window with the ssh execution string. But inspired by a rather good article at ResExcellence, I found that there is an XML key existent in any saved .term files that does the trick.
Configure a terminal how you need it then save it (either 'all windows' or 'main window') and edit, with your favourite text editor, the resultant .term file. Find the key isMiniaturized and set its value to YES. Now whenever this term file is launched, the corresponding terminal session will start in the dock. Ideal when no user interaction is required.
[robg adds: Anonymous also appended a help request regarding Terminal keyboard mapping, which I have removed as it was unrelated to the content of the hint. Unfortunately, Anonymous didn't leave an email address in their hint submission, so I cannot contact them for further assistance with their query!]