The ISH fairgrounds aren't that far from the main Frankfurt train station - about a 10-minute walk, I'm told, but if you're spending eight to nine hours on your feet, the last thing you want to do is walk when you don't have to.
Today I met an Israeli company (AMT Group) that makes an electric radiant heating mat. They were happy to give me some English-language literature and to let me know they have a U.S. distributor (Mohawk, they told me).