Surprisingly, it wasn't any harder to do five different shades than it was to do one. Even for a solid color, you grab small sections of hair at a time, so I just had a bunch of ramekins full of various colors and randomly chose a color for each section.
I'll know in about two hours whether this was a very good or a very bad idea. I'm pretty sure it will be one or the other, and not a meso-meso one. I'm cautiously optimistic.
Update: The dye has been washed out, and the hair is starting to dry. Preliminary indications are largely positive, though slightly mixed. I don't think the top layer will be quite as vivid of a jeweltone as it was before, but the depth of color tone is interesting.
 Dammit, I used to get pissed at Manic Panic because the misspelled fuchsia when they named the dye Fuschia Shock. That was the single most annoying thing about the product! I was all prepared to be happy that Special Effects could spell, then I looked at the bottle of Burgandy Wine and almost yelled at it in the store.