Wow I've just rediscovered this 1970's era typesetting language! Traditionally word processors have been used as a way to produce mass-personalized documents. WordPerfect for Unix worked well in the 80's and 90's for that sort of work and Open Office could be bent to run headless to accomplish a mass mailing or mass e-mail. However; using a Word Processing for this work involves a Graphic Display component that slows the whole process down.
Enter LaTex (http://www.latex-project.org/). LaTeX is more about flowing text around rules. Youl build a file of content and rules and cast the file at the LaTex processor and beautiful documents emerge. Granted the TeX code is a bit to learn, so doing 20 letters isn't worth the effort, but if for 200 letters, the speed will blow you away. LaTex doesn't have a visual screen component, the result is a pdf or some other printable file. LaTeX doesn't have to worry about mouse clicks, so it can spend all of its time on doing typesetting well.
Word Processors lead into corners because of the way we edit (on the screen). If we are trying to fit information in a table, we think, "What font size should be used to fit the table?" That is well and good if you have a certain fixed amount of text for tha table, but what if you have mass mailout such as a statement and the amount of text in the table varies, yet the document must remain on 1 page. Furthermore, the address block must be excactly in the same place because it must fit in the envelope window.
LaTex has a command that says: "the table must be this dimension." The font size will automatically increase or decrease to fit the table. LaTex does more with more speed (far more speed), and less memory that a Word Processor.