Traveling with a 10 and 13 year old over the holidays. My in-laws live near St. Gallen/Zurich and we are interested in checking out the Christmas markets in Germany while we are there. We have made many excursions to Switzerland during the summer months. This will be our first winter stip. My boys are also interested in snowboarding.
Although I don't have any specific information, you probably don't have to go all the way to Germany to see Christmas markets. Germany may be the most well known for it's markets, but I've visited some very impressive ones in Belgium, the Netherlands and France as well. If the movie "On Her Majesty's Secret Service" is to be believe, Switzerland probably also has a very ingrained tradition of Christmas markets.
My favorite German markets have been in Munich and Nurnberg. Be sure to check the end date of the market since most of them close a few days before Christmas. The markets in Germany have more Christmas themed items, where the markets in Switzerland tend to have more gift items. Flumserberg is very popular for skiing with the Zurich locals.