DietBar is a tweak developed a few months ago by application developers for the TweakWeek project and now we finally have it available in Cydia. DietBar was designed with the idea of reducing the bar where the back/forward options are displayed for navigating through the Settings application and not only that. The tweak offers users a few extra pixels for displaying information on the screen, but don't expect to notice a major change after installing it.
Reclaim precious pixels; shrink the height of most in-app navigation bars to a minimal size.
DietBar is available in Cydia's BigBoss repo.