Hi Steve - it has allowed me to do artwork on a specific selection of tracks. the UI isn't the friendliest in the world, but it definitely works. I love iTunify and it's saved me countless hours in tagging (track numbering, copying/pasting tags, etc.), but haven't gotten it to do artwork with wav files (but have used it with non-wave with success). Cover Art handles artwork (at the album level in the itunes database not at the track level tag, which can be a single file, a few files, etc.) whether CD or upsampled / downloaded higher res files. Given it's at the itunes database level, if you pull the tracks out of your actual itunes library, it all goes "poof" but that's always the case with WAV files and itunes with any kind of tagging (at least my understanding and experience anyway)
Were you able to get itunify to tag WAV files with artwork?