I'm sure leopard print would turn out fantastic!
I use a few kinds of substances: body paints, body crayons and casual make-up kits. I also like writing some quotes and making detailed graphics using normal pens and colourful marker pens, however I don't do it too often as it may irritate the skin.
What I enjoy the most is making a stylized make-up, for example the one done in Mexico for the Day of the Dead (it's my favourite one to do ^^). I tend to use body crayons besides the usual kits for make up for that.
If you had a slightly wider choice of colours, just as you said, you'd be able to mix them to get new ones. It's so fun (at least for me!)
So do you do 'tattoos'? What substances do you actually use - are they body paints or something different?