i tried to stab myself in the gut as an attempt back in june, but failed miserably because SI kicked in really bad. i tried to run towards a wall so the knife would go in with ease, but again, SI's a bitch and i'd stop before i'd even hit the wall. hell, i even thought about hiring a hitman towards myself.
back to your question, i don't think that there would be one. if there were, it would be in a thread called "bad ways to go" or something similar. it's a painful method and most people would go for something peaceful.