neat. Actually, I was fooling around with color layouts today. Just in case you haven't heard of it, I ran across Munsell color pickers, which lays out colors according to how people perceive color.

http://www.triplecode.com/munsell/

Maybe you can add munsell later too.

What I recognized as an itch is that color pictures and theme generators would actually be better as a FF plugin, so you can adjust entire color palettes and see it take effect right on the page you're working on.