I'm somewhat late to the party, but I spent some time playing with procedural colour picking using space-filling curves (the Hilbert curve in particular). I describe the basic technique here:

http://corte.si/posts/code/hilbert/portrait/index.html

And you can see what this looks like when used to visualize sorting algorithms at large scale here:

http://corte.si/posts/code/sortvis-fruitsalad/index.html

And here:

http://sortvis.org/

I've also published an Open Source project that might be useful to anyone who wants to play with these ideas:

https://github.com/cortesi/scurve

There are some limitations to the process as described - most obviously the fact that I'm using the RGB color space which is not the best match for human color perception. RGB is convenient because it is a regular cube and therefore easy to map onto the Hilbert curve, but with a little work the process could be generalized.