Hmm....can you use a portable CO2 bicycle tire inflator to pressurize the soda bottle? That would be a nice little party trick :D How much pressure can these caps hold? Has anyone hooked up a pressure gauge to one of these caps?
I am not that familiar with kegging or building keezers, but wouldn't you want a different temperature for the wine? Beer and Pop would be fine at the same temperature, but I thought wine, depending on style, is served at a different temperature.