Colour coding folder based on files inside?

I've a small set of folders on my desktop, Inbox, Outbox, Pending and so on, and I have checks in place to notify me and colour code files in these folders if they stay there for too long.
All good and well as long as I'm at the computer when the notification pops up, or go inside the folders. I just thought that instead of using Growl notifications, I should colour the folders if there are any coloured files inside them. That way it's more in my face.
So, in short:
If a folder on the desktop contains a red file, colour the folder red.
If a folder on the desktop contains a yellow file, colour the folder yellow.
... in that order. Is this possible?
Thanks!
-Björn
All good and well as long as I'm at the computer when the notification pops up, or go inside the folders. I just thought that instead of using Growl notifications, I should colour the folders if there are any coloured files inside them. That way it's more in my face.
So, in short:
If a folder on the desktop contains a red file, colour the folder red.
If a folder on the desktop contains a yellow file, colour the folder yellow.
... in that order. Is this possible?
Thanks!
-Björn