<<Disclaimer: Verify this information before applying it to your situation.>>

I received several responses that said the following were gluten free:

Country Time
Minute Maid
Kool-Aid

I also got one response saying that they drink Tropicana with no problem.

And I also got a recipe on making your own:

2 cups lemon juice
2 cups sugar
13 cups of water

and this all makes 1 gallon of lemonade.

One serving is:

2 Tablespoon lemon juice
2 Tablespoon sugar
3/4 cup water


Thanks to everyone that responded!  =)