I never saw this discussed anywhere (maybe I just missed it).
Have you ever looked closely to the writing of "Brokeback Mountain" on movie posters, ads, the STS book, postcards, whatsoever?
The lower line/end/border/ of the upper letters (Brokeback) looks like it has been nibbled at, or frayed or.... broken somehow.
Or, with a little bit of fantasy, the space between the upper end of the "Mountain" letters and the lower end of the "Brokeback" letters could be a silhouette of a mountain range. You can see it especially at the second "B" and the following "A" in "BROKEBACK".
Look here: (hope the pic will be clear enough)