Live Comment Preview On Submit

I really, really want to implement the version of comment previewing on this site. Specifically, I am wondering how difficult it would be to transform one of the “Life Preview” plugins, such as this one so that the preview only happens when you hit the preview button. I haven’t seen a plugin for this anywhere that I have looked…

Would it be a hugely complicated transformation to make the comment start previewing upon pushing a button instead of all the time? Any ideas?