Bobby Hoyt or Charles Burton will also make them that length, as will John Getz, but every custom barrel maker has their own schedule, and it varies from customer to customer, and time to time. So just because somebody else has gotten a custom-dimensioned barrel recently from maker X in 3 months doesn't mean you will.
I wish somebody like Rice would do some runs of longer fowling gun barrels. It just seems there's never going to be enough demand for it as everybody wants their own length, profile, gauge, form etc.