Sorry I'm so late to the party, but its almost 3 a.m. and I can't sleep.
I did this a few years ago and it turned out very good. Don't have the exact recipe anymore but it went a little something like this....
4 cans of frozen lemonade concentrate
1# light DME
a long since forgotten amount of sugar. Maybe 6-8 lbs? You could always do the math and add an amount to hit a gravity around 1050.
5 gallon of water
Once fermented, kill the yeast off with potassium sorbate, and back sweeten to taste, keg and force carb.
My turned out surprisingly good.
I did something similar, but used honey in place of sugar, and champagne yeast. I used 2 cans concentrate, 1/2lb DME and 1/2 lb honey per gallon. Ended up wicked dry, but some Splenda later it was really good, and strong...