A Call to Bavarian Catholics to Have Commissioned a Tiara and to Give it to Him

His own are going to have to do it, this is the custom, laymen. 

Somebody ought to pick up the ball and run with this one.

But 4.5 years is already too long, so get it done now, even if just for the museum or posterity sake. 

"On June 29th, he [Pope Paul] left the Vatican, this time for the Roman church of St. Charles Borromeo to celebrate Mass according to the Ambrosian rite for a delegation of pilgrims from his own city of Milan, led by the mayor.  They presented him with the new triple tiara that was used to crown him at the coronation ceremony - a tall, rather tapered, and Gothic-looking crown, fashioned according to a design that the new pope had approved himself."

-Vatican Council II by "Xavier Rynne" (Francis X. Murphy), p. 142.