Here is my homemade (because I'm cheap and attempt all organic ingredients) mix:
2T Organic Tapioca Matlodextrin from Nature's Flavors
1T organic Cane Sugar
1/4 t organic pin salt
1 packet of (non-organic) True Lemon or squeeze of 1/2 lemon or lime. True Lemon packets are handy for taking along baggie of extra mix on long ride.

It tastes fine, has about 100 calories per bottle, and is not too sweet which leaves a clean feeling and not a sticky sugary mouth feel.