I wanted to override the default Bootstrap modal so it's variable-width, and height-optimized.
Add "modal-wide" to the main modal div, and adjust the width in the CSS. In this example, I'm using 90%.
Since I'm using jQuery to set the max-height of the content area based on the browser dimensions, the modal will be only as tall as necessary, and will provide a scrollbar if needed.
Normal Wide, Tall Content Wide, Short Content