A few years ago we had lunch at Rock Bottom Restaurant and Brewery. While the food isn't anything to rave about (it was fine...just nothing extra special), I had a non-alcoholic drink from the menu that was fabulous. Thankfully the ingredients were listed on the menu. It was so good that I asked the waitress if she could tell me the proportions. She was happy to do so!
Now, I don't recall what the drink was called, but I have named it Lemon Peach Fizz. This particular drink is no longer on their menu, but a similar drink with mint leaves has replaced it. I tasted that one recently and it was a little sweeter than the original...not as much to my liking.
Because we frequently have college students over for barbeques, I started serving this when they come over. Kids as well as grown ups love it. And, for the over-21 crowd, it's pretty good spiked with vodka too!
Lemon Peach Fizz (adapted from Rock Bottom Brewery)
In a 16 oz. glass:
Fill with ice
Fill 70-75% of the glass with Sierra Mist
Add lemonade until the glass is nearly full (leaving some space at the top)
Add 2 squirts of peach flavored syrup*
In a 3 gallon jug:
Fill with ice & add:
1 can frozen lemonade
1 liter water
2 liter bottle of Sierra Mist
1/4 cup peach flavored syrup*
(Adjust flavorings as needed)
*You can find peach flavored syrup in the coffee aisle, along with all the other flavors (vanilla, raspberry, etc.). The Torani brand seems to be widely available in grocery stores. Not all stores have peach, though! I had ours special order it for me.
Another source is a local coffee place, though the price is likely to be higher. Torani and Monin are both brands readily found in coffee shops.