modify rss feed

I’ve been trying to figure out how to do this, or see if someone else has done it, but I have been successful in either yet.

I want an rss feed that is in between the full one and the sparse summary. What I would like is an rss feed that basically outputs the equivalent of the front page – HTML with images, with the more tag rendered, so that I can control paging of articles in my rss feed.

I tried to edit wp-rss2.php and substitute the the_content() call from index.php, but that just gives me a full article feed.

Does anyone have any pointers / has anyone already done this.