Hey all -
yeah, I know Dan from ShowlistAustin from when I lived in Austin, and I talked to him about ShowlistDC before I set it up (the way we've coded our sites is completely different from each other, too, interestingly enough).
Anyway - no, there's no RSS feed for what shows have changed, because I power the site with an offline database and refresh the files every night. I'm thinking about adding a page for "shows that are new or changed over the past 7 days", but given that I'm adding/changing/etc. over 100 shows a day, that list is still pretty long. It's certainly a subset of the main concert listing page (which has ~1,800 shows), but it's a very large subset nonetheless.
Anyway, if you've got any other idea/suggestions, feel free to let me know.