I've been looking over your posts here recently and you have stated there there will be no character customization - if that's still the case ignore this comment - but if you are open to adding some more minor character customization at some point in the future then I have a few to suggest:
Eye color: Nothing fancy just a choice between 6 to 8 colors.
Hair color: Same as eye color - a choice between 6 to 8 colors.
Body tan: A simple yes / no choice - tan would be uniform aside from sensitive skin locations like the genitals, anus, nipples - sensitive areas would retain a flesh pink color (for lack of a better color description).
I suggest the following eye colors: Blue, Green, Brown, Amber, Red, Silver, Black.
I suggest the following hair colors: Brown, Black, Blond, Red, White, Blue, Green
The interface could work like the following:
[Character Customization] > [Eye Color] > [Click a colored box] > [Save and return to main menu]
[Character Customization] > [Hair Color] > [Click a colored box] > [Save and return to main menu]
[Character Customization] > [Skin Tan] > [Click a check box] > [Save and return to main menu]
Nothing to fancy, just some alternate color options for variety which I suspect would be less difficult then character mesh changes like breast size / character height as example ... but I'm not a game developer so that just a guess.