When you talk about "navigation controls" - what do you really mean? 🙂
Is it "just" the Next/Previous functionality, like Josh mentions? What about initial extent? Or full (some sort of max) extent?
Which of them are most important (and thus what do you think should be our priority)?
Are you asking for Robert's buttons a la http://gis.calhouncounty.org/flexviewer2.0 ? 🙂