Need to keep image as top post on front page

For our newspaper site, we always have a pretty or at least important photo at the top of the front page. In Wordpress, that means it's the most recent post, so we have to make sure all other posts have earlier publish dates. No problem with that; we can do that.

I have the excerpt option set to show only excerpts on the front page except for the first post, which will show the full post, so we get the image to show. However, it will also show the whole post, which we don't want if the post is rather long.

I came up with a klunky work-around: I create a post with just the image at the top and a short blurb. I create another post with the image and whole article, and make sure I publish the short one last. Of course, now I have 2 posts with the same image and part of the same content showing in the Recent Articles list in the sidebar, and everywhere else.

http://larchmontgazette.com/wp27/

Can you think of a better way? I thought of creating a new category called Top Image and assigning the short one to that, and then find a way to keep that category from showing at all in the post lists except on the front page.

Or could this be an option in a future release, or a code tweak now?