I checked in to this and it looks like it is possible and hopefully won't be too hard to do. I'll work on this now that I've got my maemo.org page up for coverfinder. My plan is to add a 2nd dropdown to allow the selection of Music (current default), Books, and DVD.

Oh so get this, the current search is will allow the following:
artist:<search artist>;title:<search title>

So searching for Eric Johnson's cd Tones:
artist:Eric Johnson;title:Tones

Of course Books will have to support:
author:<search author>;title:<search title>

And it seems DVD should allow:
actor:<search actor>;director:<search director>;title:<seach title>

Frank