Today, I improved the color-picker for the shape and removal-rule editors. The color-picker itself is very simple - just a collection of square divs that you can click on to change the color of the next blocks you click on in the shape grid.
Prior to today, I was just using a simple ROYGBV list, packing it into an array and rendering the divs server-side. I'm still rendering the divs server side, but I'm iterating through color values, stepping from 0 to 255 by 64. This provides a nicer range of colors to choose from.
Ideally, I'd like to implement a photoshop-style color chooser, or at least order the divs into blues, reds, and greens (I may do this here in a day or two) - but this can wait for a bit.