This is something I mentioned before that I would love to see added to Nox, covers in wall view would be a huge improvement in my opinion. For my setup, about 95% of my movies are blurays so I use a little cheat. Download the GIT version
https://github.com/BigNoid/Aeon-Nox and copy the media folder over the one with from the regular download
Go to a windows explorer and type %appdata% then roaming/XBMC/addons/Nox folder to find the media folder (this should be correct, I'm not in front of my setup to verify 100%)
Do a search for textures.xbt in the skin folder and delete it
Find the clear case overlay - it's in the thumbs folder I believe and copy the bluray cover into it with the same name (overwrite it)
Then enable clear cases in wall view, you will see bluray covers
Of course this doesn't work for different file types (dvd, sd, etc) it will only show bluray covers over everything. Better than nothing though for me.
Hopefully this helps, I might not have been real clear... watching game 1 of the finals right now.