I updated my ExactImage-based QuickLook plugin to also support camera RAW images.
Just some week ago I got myself a Sony Nex 5 camera, and used to shooting RAW images for the superior post-production quality with my former, aging Canon EOS 350 I had to notice Mac OS X (10.7) does not support the Sony Nex RAW images by default. There is a camera raw update, but it apparently only installs with iPhoto or Aperture installed, which I do not plan to purchase.
If you have another image format you like to preview on the Mac just let me know! Especially if you have camera RAW images that you would like to preview, I likely have to add the file UTI for other files to load, too.