My Johnny-5 project with Arduino and AdaBerries

Hey guys I got a few questions regarding a project I'm working on. I found one other thread related to this( but I appear to be further along in my project.

So I bought the Johnny5 robot kit from and my plan was to swap out the microcontroller and motor controller for a Arduino Mega and a motor sheild as a base setup, then add an array of sensors and sheilds to make an autonomous robot pet.

Here is a quick brake down of the base Johhny5 system (batteries not incuded in kit): 2 x 12 volt gear head motors 12 x servos 1 x SSC-32 microcontroller 1 x Sabertooth motor controller 1 x 12 volt battery (motors) 1 x 9 volt battery (servos) 1 x 6 volt battery (microcontroller)

Everything work according to plan...well almost. After ironing out some kinks I have managed to get Johhny rolling around as intended in a semi-autonomous manner. Animating the upper torso is pretty much straight forward servo control. After getting the basics under control naturally I though to myself "What next?" and off I went to my local parts dealer...This is what i bought for V1.5 :

Sensors: 2 x Ping sensor 2 x tilt sensors 1 x PIR sensor 4 x proximity sensors 2 x IR sensors 2 x force sensors (for hands)

Sheilds: GPS - MicroSD - VoiceBox - EasyVR - 16-ch Servo -

So my question is in regards to unforseen problems that could arise from stacking multiple sheilds. I'm going with the manufacturers recommendations for power supply. Any imput would be greatly apprectated.