For many San Franciscans, talk of the city’s mansions conjures images of the so-called “Prestige North” — the trophy properties of Pacific Heights, Presidio Heights and Sea Cliff which are historically the most expensive single-family homes San Francisco has to offer. Indeed, when 2701 Broadway sold earlier this year for $31M it became the highest priced sale of the year. Nonetheless, there’s been a remarkable shift in the number of multi-million dollar home sales in recent years to the …