I know they exist, because I have a laptop keyboard in my car. the ribbon connected to a controller, which then plugged into a ps2 cable. its exactly exactly like my touchscreen, with the ribbon going to the controller, then a USB cable that plugs into that.
My buddy scavenged one and gave it to me for my car. I asked him about it, he shrugged his shoulders, said he scavenged it that way.
the ebst I can do for you is to say they do exist, we will be dammed if we know where or how