A Nintendo patent shows that Nintendo is, or was, considering the graft of Wii U-like features onto the regular old Wiimote. The company applied for a patent for a device that adds a touch panel to the Wiimote, using an infrared LED and mirrors to feed info about the position of your finger into the Wiimote's IR sensor. The patent describes using it as a mouse pointer or a drawing interface. You know, touch panel stuff.
The tech doesn't exactly emulate the WiiPad, as the touch panel is just for controls, and isn't a screen. It's unclear whether this is something Nintendo is planning for the future -- for enhancing Wiimotes for use on Wii U -- or if it's just an idea someone cooked up.