I don't think you're going to find any tea or coffee that will lighten hair, since it would have to be 'chemically' enough to strip the hair of pigment. I've used coffee to darken my hair, but it's very subtle (and my hair is dark blonde) and takes several applications.
Here's what I do. Brew a full pot of coffee (I make mine extra strong) then let it cool for several hours. Plug kitchen sink, and pour coffee over hair, letting the excess drip into the sink. Then using a cup I get the excess coffee from the sink and continue to apply until I feel my hair is thoroughly saturated. I put hair in a plastic bag and let the coffee sit on it for several minutes to an hour and rinse.
I stopped doing it because it simply wasn't worth the hastle for the very subtle difference it made.
I've also used black 'henna' (it's not true henna, really I think it's indigo dye) and left it on for just a few minutes. That worked really well, but the indigo stained my tub when rinsing - so that wasn't worth it for me either.
Best of luck, and I'll keep watching this thread for ideas. I'd love to have darker hair too, but I hate chemical coloring.