The work on new "big" (i.e. middle version number change) QComicBook release
has started. You can track this work in the dev/0.8.0merge branch of the git repo; this branch will get merged back to master branch once ready.
One of the most important internal changes to be included in the upcoming release is switching from using widgets to Graphics View Framework provided by Qt. This switch made it possible for an easy and nice implementation of Zoom Lens, so QComicBook 0.8.0 will finally see this much welcome addition! Long-term, the switch Graphics Framework may result in improved QComicBook performance and make it possible to use e.g. OpenGL backend to speed up scaling etc.
The new 0.8.0 release will also bring PDF reading support (as I already indicated earlier) via Poppler library, which is a new dependency starting from this release.
I'd like to push the new release out by end of this year if possible, but the scope of changes related to new graphics framework is substantial and there are still some rendering-related bugs, so it may slip to early 2011.