I just made a soap with lard, honey, milk and oats in it. Not sure what exactly caused it to turn color but it's a warm brown color...probably the combo of milk and honey is my guess. Smells fantastic too!
I used a strong green leaf tea infusion the other day for my lye, which went like milk chocolate. You could try a really tiny bit of green leaf tea to just tinge the lye water see if that goes ok. Also vanilla EO can I believe tint a light tan.