Multiple Shields on Arduino MEGA 2560 R3

Just Wondering If its possible to mount the Arduino Motor Shield R3 and the Arduino Wifi Shield on the same Board (MEGA).

I found this: Stacking Arduino Shields | Freetronics

but i have hard time determining if the two shield could be used together. I have an Arduino Uno, would it be possible to mount the motor shield on it, and then hook up the two micro controllers together, UNO being the slave, and MEGA the master?

thanx for any suggestions in advance.

This shield has two separate channels, called A and B, that each use 4 of the Arduino pins to drive or sense the motor. In total there are 8 pins in use on this shield. You can use each channel separately to drive two DC motors or combine them to drive one bipolar stepper motor.
The shield's pins, divided by channel are shown in the table below:
Function pins per Ch. A pins per Ch. B
Direction D12 D13
PWM D3 D11
Brake D9 D8
Current Sensing A0 A1

Arduino communicates with both the Wifi shield's processor and SD card using the SPI bus (through the ICSP header). This is on digital pins 11, 12, and 13 on the Uno and pins 50, 51, and 52 on the Mega. On both boards, pin 10 is used to select the HDG104 and pin 4 for the SD card. These pins cannot be used for general I/O. On the Mega, the hardware SS pin, 53, is not used to select either the HDG104 or the SD card, but it must be kept as an output or the SPI interface won't work.
Digital pin 7 is used as a handshake pin between the WiFi shield and the Arduino, and should not be used.

For the record a good resource for comparing shield pin use is