The signal is available and can be used. Now I need a day to find it.

-R

From the Escape/Mariner Hybrid Modifier Guide...

Vehicle Speed Signal

Note: If non-OEM tires are mounted on the vehicle, the pulse per mile frequency will change.

Note: Any device connected to the vehicle speed signal (VSS) circuit will require a high impedance of at least 1 megaohm. If this speed signal is compromised (by using a device with low impedance), the navigation system may not be able to show the correct position of the vehicle as accurately.

The vehicle speed signal (VSS) is sent from the brake system control module to the navigation system through circuit 679 (GY/BK). If the vehicle is not equipped with a navigation system, circuit 679 (GY/BK) ends in connector C210 pin 5. With OEM tires on the vehicle, the signal is 31924 pulses per mile.