I think Hajk (next to the train station in Zurich, that is platform 3 to be more precise) has them. Probably also Transa or other adventure / outdoor type shops.
Well, this is a thermo box to keep warm with 2 smaller boxes for food inside. I couldn't find the ones (in the link of 1st post) in Zurich so my mum sent it from home to me. Mine is Japanese style. I did find a similar one in Coop city in Bellevue, but it's quite big and look urgly. It's made in Germany and costs about 70 CHF.