(I don\'t want to hear about how crazy I am to want that! :)
Focus-follows-mouse is also known as point-to-focus, pointer focus, and (in some implementations) sloppy
Give DwellClick a try. Although, it's not for its intended purpose, the auto-click behavior has a side effect similar to auto-raise or focus-follows-mouse.
Personally, I only use the feature of left clicking after my cursor movement comes to rest, but there's also clicking with modifiers and a window dragging assist that's quite handy.
It's also a little frustrating while web browsing since you'll either want to disable the app or be more conscious of where the cursor rests (e.g. not on any links or buttons you don't intend to activate).