I had the same idea a while ago but could never decide on the best way to implement it... then I forgot about it all together.
Having a thread is a another option. The advantage of a thread would be that those that want to help could subscribe to it and get an email notification sent to them. Most of us have smart phones and our phones will let us know when we have an email.
I still think that just making a thread in the proper section with "URGENT HELP NEEDED" in the title would work best. Somebody will see it pretty quickly and the thread would be there to reference later.