I've carried on working on DCDisplay. I've been adding a check all files mode, it recurses all the hard drives on your computer and examines every archive (zip & rar). It reports any problems it finds, and also any duplicate files (it does an image checksum of all the images in the archive, so if you have cbr and cbz version of the same contents it will match as a duplicate). I use a html template match that I wrote, so you can style the output (there is a simple default template with all fields present in a table.).
It generates a thumbnail of the first page in each archive that can be used in the html output, and it saves the results as it checks the files so you only have to do it once (and then the next time, it will just examine the new files although it will still compare with all the original files). It reports problems it finds, including nested archives (zip files inside another zip for example), thumbs.db inside the archive (no point at all, and increases the size). MAC format zip (MACOSX directory, which causes CDisplay to crash, although DCDisplay can handle it with ease), corrupt images, and malformed archives.
I've also replaced the 7Zip extractor, and now use native C# code to read rar and zip files with no dll dependency. I have a few TB of data that I am testing it with, so it will take a while to run (it's been running for over 30 hours non stop and seems to be working fine), once the report is generated I will update the release with a new version.