It is very likely possible, but I don't know if there is currently existing technology for it on Flex (polyimide based). By vaporizing thin metal layers, it is possible that there would not be just one layer. For example, typical MnO, CrO, CoO oxides for NTC temperature sensors. NTC is also produced in flex, where a small sensor bead is mounted and then it is encapsulated in polyimide. It will also help to look at the technologies of hybrid PCBs on ceramics, where resistors and capacitors are normally made, which are then precisely adjusted with a laser.