During a recent "you have reached the end of the web"-style browsing session, I stumbled upon what looks to be a powerful tool for color research: 3D Histogram, an open source web application from Minneapolis-based Third Ave Design.
3D Histogram "provides a visualization of the overall color composition of an image by placing cubes in a 3D space whose X, Y, and Z values correspond to the R, G, and B values of the color being graphed." Each cube is "painted with the color it represents, and then sized according to its relative frequency in the image."
The fashion-related applications are endless--you could use it to research color trends, to get a firm grasp of color theory, or to understand the effects of lighting and texture on color. Above are yields from a "swatch" image of the Fall '08 Thakoon dress pictured at left. Now if only the data were downloadable in spreadsheet form...