Search so totally sucks these days so the best I can do at this point is search on "Brazilian" and not narrow it down to SF.
You might look at SF markets in that list such as Mercado Brazil and Bossa Nova to see if they have it. Also, look at the SF Brazilian restaurants since they often have a few groceries selling essentials. Give them a call and ask
Ninth Annual Chowing with the Hounds Picnic! October 3rd, 2009
I saw dende oil somewhere a few months ago when I was searching for Styrian pumpkin seed oil. It was most likely Rainbow Grocery (they have the biggest selection of exotic oils), if not there it was Bi-Rite or the big Whole Foods on 4th St.
Fresh yuca (aka cassava, manioc) is readily available around here, no need to seek out frozen.