Note: You must have Apple's developer tools installed, specifically Interface Builder. Here's what to do:
- Locate Safari.app in the Applications folder, control-click (or right-click) on it and choose Show Package Contents from the pop-up menu.
- Open Contents » Resources » English.lproj
- Make a backup copy of Toolbaritems.nib.
- Open Toolbaritems.nib; it should open in Interface Builder. The following steps are from within Interface Builder.
- Open the Window panel
- If the Inspector isn't already open, hit Shift-Command-I
- Select one of the location/search bar SplitViews by single-clicking on the split handle between the two fields. The location and search bar should both be highlighted.
- In the Inspector, uncheck Attributes » Split View » Layout » Vertical.
- Select the search bar only by single-clicking it. It should only highlight the search bar in blue.
- In the Inspector, uncheck Control » State » Enabled and check View » Drawing » Hidden.
- Save and quit; you're done
[robg adds: I haven't tested this one. I did, however, confirm with the author that he hasn't had any keychain-related issues in 10.5 (due to Safari being a signed application).]

