foo_uie_albumart_mod
It has an option to select the background colour. It also allows for cycling through artworks from various sources.
C.
EDIT: Just to be a little more helpful, when it comes to sources it's very configurable and allows for a hierarchical selection: THIS, IF NOT THEN THIS, OTHERWISE THIS, THEN THAT etc..
Example:
The following would look for the album cover in various file namings then BACK.*, then ARTIST1, ARTIST2. Notice the "-" which acts as "OTHERWISE THIS". So, if it finds front.jpg it will skip looking for cover.* and folder.* and images/nocover.* and go straight to look for (e.g.) Mozart1.jpg. Hope that helps.
$replace(%path%,%filename_ext%,)front.*
-$replace(%path%,%filename_ext%,)cover.*
-$replace(%path%,%filename_ext%,)folder.*
-$replace(%path%,%filename_ext%,)images\nocover.*
$replace(%path%,%filename_ext%,)back.*
$replace(%path%,%filename_ext%,)images\%artist%1.*
$replace(%path%,%filename_ext%,)images\%artist%2.*
C.