The best thing ever!

Originally uploaded by Jeffery Simpson.

I have fallen in love with / become addicted to the ice tea lemonade cocktail made by Starbucks. My Dr. Frankenstein like attempts to reproduce this tasty brew have all failed. I bought a jug of something very similiar at Trader Joe's when I was down in Seattle, but it's running out too quickly.

If I can figure out the right combination of ice tea to lemonade then I can make it at home for pennies a gallon, until that day comes I'm stuck either buying the bottles at the dollar store and trying to mix them while at work, or if I want the real magic going to the Starbucks and shelling out for the real thing.  I can't afford the real thing though, not every day anyway, so I need something that's even better than the real thing. 

Has anyone been able to make this drink on their own?  What's the secret?  Once again, where am I going wrong?  Is there some secret ingredient in the Starbucks drink, something like crack that keeps me craving it?