Over my year or so here i have had multiple occasions in which I would love to have a suicide emoticon. Most recently was the "gang" post in the off-topic forum. It wouldn't be hard to make or find, but would include a gun and a "not-so" smiley face. Then some blood.
Thank you for reading my suggestion, even if you don't do anything about it.
oh, and I bet you guys get this a lot, but you need to fix the search engine