What types of flooring can be used with electric radiant heat?
Some electric radiant systems can be used with laminate floors, e.g. http://www.suntouch.com/mats/, or even floating/engineered wood floors according to http://www.thermosoft.com/radiant-floor-heat/ .

Laminate might be a good option as it can flex and is easy to install. Check with the radiant heating manufacturer to ensure you're using a flooring and adhesive that are compatible with the floor heat, but I doubt the temperature will be a problem -- radiant floor heat probably doesn't get much hotter than your floor would naturally get on a hot summer's day with the windows open.