Stéfan pointed me to this new visualization library, D3.js – Data-Driven Documents. The image above is from their Co-Occurrence Matrix (of characters in Les Misérables.) Here is what they say in the About:
D3.js is a JavaScript library for manipulating documents based on data. D3 helps you bring data to life using HTML, SVG and CSS. D3’s emphasis on web standards gives you the full capabilities of modern browsers without tying yourself to a proprietary framework, combining powerful visualization components and a data-driven approach to DOM manipulation.
Take a look the examples Gallery. There are lots of ideas here for text visualization.