Home brewed iced tea (black tea) and green tea.
You've tried EVERY sweetener, really?
Have you tried stevia? It's NATURAL. And you don't need much of it to sweeten.
The two brands I've had success with are:
1) "Stevia in the Raw" (fairly cheap, with a SLIGHT aftertaste that's not bad. It's good for iced tea because it adds a freshness taste to it)
2) "SweatLeaf". This is more expensive than SITR, but it has NO AFTERTASTE whatsoever and even contains prebiotic fiber for good health.
Think of food as fuel for the body instead of feeding emotions