Any dynamic scripting language will work. Just set up a random number generator and pull the information out of an array (or simpler just use a couple of if statements to display or not display the content).
The already indexed static pages can be benficial only if you set up 301 permanent redirect pages for each of the static pages (This only applies if the page name changed .i.e. from index.html to index.php or index.asp. If the file name stays the same, you will have no problems whatsoever) Otherwise, the search engine will have to "refind" the content and index it just like it is a new page.
I have several articles that I would like to rotate on my home page. Better still, might be to have the first paragraph rotate of each article rotate, and link to static pages deeper in the site. I assume this requires some kind of dynamic content script. Do you have a recommendation for this?