Fun OPAC feature?

What if this where an online catalog feature?

This retrieves books based on the color of their book cover (using hex values)! How fun would it be to add this to an OPAC? Heck, even as a tool for librarians to assist with those "Uh, I need to use the green book." requests. Heck, I just like clicking "pick random colour" button and seeing what shows up! Just imagine the possibilities.

I wish I were this clever. Neat idea folks at University of Huddersfield (wherever in the UK that is). Saw this over at Jessamyn's site under one of her talks.