There are no kits that I know of for champagne. However, you can use kit wine to make a sparkling wine, and you can use them in similar preportions to retail versions. For instance Dom Perignon is 52% Chardonay and 48% Pinot Noir. But these are pressed quickly and only the first bit (some say 50%) of the juice from the pressing is used for champagne. This keeps the coloring to a minimum. They then age the bottles on the lees for at least 2 years (typically more) and then the recipes for Liqueurs d'Expedition are all proprietary. And don't forget about disgorging the bottles, which is sticky and difficult. I'll be trying my first batch this fall, in the mean time I'd suggest doing as much reading as possible and collecting champagne bottles.