If I have some time tonight, I'll work on a hair pallet for the heads. There's ultimately a few ways of doing this and it has to be decided early on by anyone who'd want to use this stuff. It basically comes down to how much information the programmers are willing to store and how many sliders they're willing to add at character creation.
1. Make a bunch of sprite sets that are set sprites, which is what P3D has now with it's single slider. In this case it would just be increasing the number of options.
2. Separate the bodies from the heads and put all male and female bodies on top and all of the heads on the bottom, allowing any head on any body. This leaves avatar data storage at 2-4 pieces of information, which body and which head. If you make a slider for colors, you can cut the time it takes to find what you want significantly.
3. If you separate gender for heads and bodies, you add another variable in, but you make the number of heads and bodies you have to sort through to find the one you want get cut in half. Also, gender information can be handy to have in making a game for story and what not, so this info can be pulling double duty. With 0 for male and 1 for female, you can still use math to pull the right sprite, too.
4. Hair colors... If you want to make just four hair colors per head style, you increase the number of sprites you have to sort through, but you can add another slider for that, too. Pick Red's hat in blue and then black hair.
5. Skin tones get over looked in JP games because they aren't the melting pot that some countries are. They make what the see everyday and there's nothing wrong with that. I don't think it would hurt to consider this option for two, maybe three skin tones- pale and dark, maybe add a medium. This will have a bigger effect on the number of sprites than one would think, though.
Some math to show the number of options with, because it gets big fast.
4 bodies /w heads(M&F) x 4 colors = 16 character options
4 bodies x 4 colors x 4 heads x 4 colors = 256 combos which can be cut in half with gender segregation
if you make for hair colors for those heads = 1024 combos without gender segregation
It just goes to show that you can add a lot from relatively little with a bit of planning.
-Rabbit