Take this for what it's worth, since csr's haven't been reliable in the past for information, but a csr from the North Florida call center told me yesterday that WGN (among 5 other networks including BBC America) was scheduled to go HD before the end of the year. And no, the Travel channel wasn't one of them. One was some kind of new terror channel. I'll believe it when I see it.
Chiller hd, perhaps?