Don't think there's a separate keyboard for doing this. It would amount to a massive touchpad, which would probably be more expensive than a regular keyboard.
You can run these and swipe using a mouse or touchscreen (or I guess a touchpad).
http://www.intowindows.com/swype-keyboard-for-windows/
http://touchpal-smartinput-win8.software.informer.com/1.2/