Have you ever used the Stevia herb?
Rather than processed Stevia, you can buy a plant and just use the leaves. We have a plant in our kitchen and it is great for teas, water, coffee, etc. I don't think it tastes anything like the processed Stevia.
I use it with my lemon verbena plant, and a little mint and you are good to go.
My daughter eats the leaves, and likes it in her tea.
oh.. here is a little info on Stevia