OK, well you can't get the Pope's socks, but you can get pretty close.
I picked up a few pair of socks from Gammarelli's last week. I thought I'd share a few pics with you all.
Gammarelli has been in business for over 200 years; they provide garments for Catholic clergymen and also provide bespoke garments for the Holy Father. None of the items they make will be useful to most of us, but they have some pretty sweet men's hosiery.
They make a special "secret" sock for the Pope, the weave is made only for him, but for us laymen they carry a normal white sock. They also stock purple (for Monsignors and Bishops) and Cardinal Red for, well... Cardinals.
The back side of the Pantheon is just around this corner to the left.
Sorry- the pictures of the other socks were blurry, but you can see the red ones here. I'll try to snap a few next time I wear them.