You dug up an old thread. In November DirecTV will start offering our locals in HD, but I don't think PBS is in the lineup. Only, time will tell.
They are still the local feed. In my DMA, Bismarck-Minot, PBS is only SD for some reason and DirecTV crops it instead of taking the -2 feed that is letterboxed.
As I said last November, our PBS offers three OTA channels; -1 is HD (possibly the national feed), -2 is the locally produced content and -3 is Create.