I know someone here was looking for them. I just saw a bin of them at Mi Tierra on San Pablo in Berkeley, one block south of University. They also had some ripe (or semi-ripe--they were yellow, not black) plaintains.
I found them as promised at Monterey Market. Dark green and rock-hard. Though they no ripe ones, which probably means that like Berkeley Bowl they get a batch in, have only green for a while, then only ripe for a while.