I wrote a script that'll check a series of future IDs (50 at a time) and tell you which have articles.
[spoiler="Screenshot"]
[Image: http://s2.postimg.org/80n13f93d/shot.png]
[/spoiler]http://rydian.net/tools/mabinogi/newschecker/
(pls dun hammer my host 24/7)
Mabi's news IDs are in base-62 (0-9-A-Z-a-z, 10+26+26) so it decodes the ID to a number, then runs an incrementing loop to check a bunch. I use cURL to fetch response headers for each generated URL (with the no-body option because get_headers() is lazy and downloads the whole page). Nexon's web server sends an HTTP 200 when an article exists, and an HTTP 302 as a redirect to the main news page otherwise so it's a simple comparison.