#http://swedishcampground.com/safari-4-hidden-preferencesHaving a quick poke through the new Safari binary yields the following strings:
$ strings /Applications/Safari.app/Contents/MacOS/Safari | grep DebugSafari4
DebugSafari4TabBarIsOnTop
DebugSafari4IncludeToolbarRedesign
DebugSafari4IncludeFancyURLCompletionList
DebugSafari4IncludeGoogleSuggest
DebugSafari4LoadProgressStyle
DebugSafari4IncludeFlowViewInBookmarksView
DebugSafari4TopSitesZoomToPageAnimationDimsSnapshot
DebugSafari4IncludeTopSites
*NB: Need to restart Safari after changing any of these.*##DebugSafari4TabBarIsOnTopThis moves the tab bar back where you expect it to be:
$ defaults write com.apple.Safari DebugSafari4TabBarIsOnTop -bool NO
##DebugSafari4IncludeToolbarRedesign and DebugSafari4LoadProgressStyleWhen both set to NO it restores the blue loading bar behind the URL.
$ defaults write com.apple.Safari DebugSafari4IncludeToolbarRedesign -bool NO
$ defaults write com.apple.Safari DebugSafari4LoadProgressStyle -bool NO
##DebugSafari4IncludeFancyURLCompletionListSwitches off the new URL autocomplete menu and goes back to the original one.
$ defaults write com.apple.Safari DebugSafari4IncludeFancyURLCompletionList -bool NO
##DebugSafari4IncludeGoogleSuggestTurns off the new Google suggest menu.
$ defaults write com.apple.Safari DebugSafari4IncludeGoogleSuggest -bool NO
##DebugSafari4IncludeFlowViewInBookmarksViewUnknown.
##DebugSafari4TopSitesZoomToPageAnimationDimsSnapshotUnknown.
##DebugSafari4IncludeTopSitesDisables Top Sites feature completely.
$ defaults write com.apple.Safari DebugSafari4IncludeTopSites -bool NO
##Undoing changesJust run the defaults command with the `delete` flag for the appropriate key you wish to delete.
$ defaults delete com.apple.Safari <key>