// Assuming the latest version was installed using RubyGems (gem install sass --pre)
// The path depends on the exact version, of course. Tab completion to the rescue.

cd /Applications/LiveReload.app/Contents/Resources/SASS.lrplugin/lib
mv sass sass-bundled
ln -s /Library/Ruby/Gems/1.8/gems/sass-3.2.0.alpha.275/ sass