»In which I still cannot lock the screen

I have long struggled with OSX's lack of resource for locking the window manager and the screen. I am not content with the Hot Corners available in the Screen Saver Preferences Pane: not only might pointer bounce away from the edge, but it requires mouse movement, and I prefer a hotkey or a command-line to do this. I am also not happy with the two-click lock icon provided in the Menu Bar by the Security Pref., for reasons you now understand.

I have tried hacks such as a short shell + AppleScript to invoke the ScreenSaverEngine (/System/Library/Frameworks/ScreenSaver.framework/Versions/A/Resources/ScreenSaverEngine.app/), which is what I thought locks the screen. Although this is not the right thing to do, because I might end up with multiple ScreenSaver instances (and a totally unlockable screen!). Apparently the right way to start the screensaver is the private API used by the keychain menu item to lock the screen, and this is used by the LockTight application. I want to try the MenuMaster program, which allows hotkeys to bind to things like scripts, but am a little nervous about third-party OS extensions.
UPDATE:
Quicksilver's LockScreen plugin loads the Keychain menu extra internally as a bundle, and then invokes the keychain menu's "_lockScreenMenuHit" selector directly.which calls the same code path as selecting the screen lock icon from the keychain menu.