So here comes the answer

Ok, so perhaps his eminence the ex-cardinal Ratzi didn't have a wardrobe stocked with Pope-drag ready for his enthronment, instead they were on show in the window of Gammarelli, the ecclesiastical tailors. Now, since I doubt I can walk in off the street and get one of those perky little numbers, why do they display them in the window?

The three white cassocks on display in the window of Gammarelli Ecclesiastical Tailoring come in small, medium and large, because no one knows what size the next pope will be.
In the world of religious raiment, few distinctions are as great as counting the leader of the Roman Catholic Church as a client. So when 115 cardinals meet on Monday in the Sistine Chapel to begin a conclave that will select the next pope, the tailors of Gammarelli will be especially interested to see who will emerge wearing white.
Filippo Gammarelli, 63, whose family has been making papal clothes since 1798, including those for John Paul II, is hoping that the next pope, who will eventually step out onto the balcony of St. Peter's Basilica modeling a Gammarelli cassock for millions, will like the fit.
That has not always been the case.
For the plump John XXIII pins and tape had to be used for last-minute alterations, while in 1914 the diminutive Benedict XV swam in his white silk simar, the special cassock worn by popes only.