I'm going to try to make a stevia extract with my stevia leaves as soon as my plant gets big enough. It's pretty easy: combine vodka and clean, chopped stevia leaves in a small, mason jar. Cover and let steep for a couple of days. Strain, warm on the stove gently, to remove the alcohol, pour into a small, dropper bottle and done.
I wonder if you can clone stevia plants?
~ C