Got an Oliver Ace ready to go with tooling that will do the job. I replaced it with a newer version of the same machine. If you left the machine set up for the job it would take you maybe 5 or 10 minutes to re grind the OD of the cutter. Grinding the sides will require a bit more time but can be done. I basically got into cutter grinding for simular reasons. For the price of maybe 5 or 6 trips to the CG shop I could purchase a machine to do the grinding in house. PM me if you're interested.
As to your original question, most any cutter grinder worth its salt will grind a 4" stagger tooth milling cutter. Oliver, Cincinatti, ect
Paul