It would be great if we could define some additional art fields apart from the front cover. I am mainly interested in the back cover and maybe the disc.

I imagine in the options one could choose which 2nd field should be searched and what to call the files on disc.

front cover > front.jpg
back cover > back.jpg

Then the search windows could simple be split into 2 rows or the search result could be a tabbed window with a tab per searched art. This way the integration could fit nicely into the current gui.