have you any plans to implement a Colour space, which represents how humans perceive Colour? I am thinking about the CIE LCH space or the CIE LAB space, which Photoshop uses. Here is an explanation on Wikipedia: https://en.wikipedia.org/wiki/Lab_color_space
I think, such a tool could be handy for automated colour selection (i.e. to find constrasting colours for menus and the like).
Inside the Colour class it already uses the YIQ space to help the Colour::contrasting method to give good results. That method may do all that you need if you're just trying to create colours for menus etc.
As far as adding more public colour-space stuff, yes, that'd be interesting, but would have to involve a more general set of classes that use templates to provide all the colourspace mappings. It's certainly something that I'd like to do, though probably quite a niche feature!