That's what this new control does. Every time you click on the canvas it will open up and let you modify the current color in one of 3 dimensions.
I've put together a demo here. Please try it out and give me some feedback on how you think it will work. I'd also like to hear what you want from the general color picker interface. Swatches? RGB? HSV? Fractal Painter style triangle dial?
It's a double clickable single jar java app. Just click away.
thx,
Josh
Blasting forth in three part harmony!