<p>Dana- you do sound very sincere. Typically, the sorts of activities in which you have been involved aren’t the type chosen by resume-padders. Unfortunately, most top schools, Stanford in particular, don’t want to have to sort through extra recommendation letters. However, one extra letter shouldn’t be too much of an issue, as long as it is pertinent to your application (which I’m sure it would be) and doesn’t restate information that’s already in your application.
Another alternative place to put more information is the “Additional Information” section of the common app. On mine, I went into more detail about my tennis prowess, my involvement with youth orchestra, and my extensive community service involvement. I also included a book list. While you don’t want to put a whole essay in there (I trimmed all that into just one page), that would be a good place to perhaps go into more detail about why you’re passionate about a few of those activities. Good luck!</p>