I know CAB's batch plot routine, you'll find in Show Your Stuff can be overwhelming for a noob, but you might give it a look to see how you might integrate your own plot utility into this. As far as the job number goes, you can substr, strlen, and a few other utilities to break down and rebuild the info you want from the .dwg name.
What do your users put in place of job name?
I'll ponder the billable part. That may be something like putting a toggle in the dialog box of your own custom plot utility.