QuickLook Lightroom plugin is now available for download from Mac App Store Unfortunately, I had to choose a new display name for the plugin (“LrCat Preview for Lightroom”), because apparently having two corporate trademarks for others does not count as a valid name in app store…
This is actually not a Lightroom plugin, but a Mac OS X QuickLook plugin, which allows you to quickly peek into .lrcat files before opening them in Lightroom. The new version supports also earlier Lightroom version catalogs.