Dark Horse Comics will be putting out a 304-page comic book featuring a selection of "Steam-powered" stories this November. Left 4 Dead's The Sacrifice, a previously published online comic, will headline the book, and it'll be joined by stories from Team Fortress 2 and Portal.
Valve Presents: The Sacrifice and Other Steam-Powered Stories will sell for $29.99 from November 16. I have a feeling I may need to pick that up myself.
DARK HORSE COMICS SOLICITATIONS FOR OCTOBER 2011 [Comic Book Resources]