I'm thinking Big Kahuna might have some info as well on this...I would think using fruit in meads is similar to this...
I knew my ears were ringing
The only thing I'd say about comparing it to mead, is that mead has alcohol to help extract the flavor, as well as suppress any issues with rogue bacteria.
I would vote for a potentially cloudy soda, and just add boiling sugar water to the fruit. Seal it up, then rack gently in a few days (weeks? Months? Maybe it'll clear?) and then carb as usual. Maybe it's worth your time to add regular soda concentrate to your batch. ie. Cherry soda, or fruit and ginger ale concentrate, as opposed to strait fruit drink.
Another option is to juice the fruit, and use it with sugar and boiled water.
I also contend (theory only...I've been too busy to give it a shot) that boiling water for soda will improve the quality, as it will remove most of the oxygen, and make it more shelf stable as well. This should improve the ability of the liquid to absorb co2, and give a more rounded "Clean" Flavor.
Good Luck, and I'll be watching this to see how it goes.