Need an ability to log user operations at the beginning of their execution

Currently in mongod we only have the ability to see user operations logged when they finish (at loglevel 1). It's a very important piece of information that can greatly help in isolating certain bizarre behaviors to the application code or to the database itself.

Consider an operation that ends past the end of the logfile that we have. There would be no way to determine when it was started without waiting for it to complete.