I'd also like to request this feature. My collection, while chiefly rock and pop, includes a number of classical pieces and something like this would be a nice presentation.

In theory it could be done at the theme level, but I think it would require the use of at least one custom checkbox and some javascript support behind it. That's off the top of my head, though. Sharing themes that make use of custom fields doesn't work terribly well because custom fields are not exported with the theme, which is strictly a presentation level customization.