I'm down with fever, so I can't think of any new ideas to contribute
laptop sounds good, but remember we are doing most of the data processing offboard.
In terms of weight, we can just use the motherboard.. no need for the laptop chasis. You'll just have one big ass PIC board then. What else.. um, as ahmed said about the parallel port, I guess we need to multiplex it
We can also use other I/Os; the mic input/sound output can be used as a ultrasonic detector, with modifications of course. We can safely rid the screen entirely, as long as you have a VGA output!
I like the tank track idea. Looks cooler
We can still use a microcontroller, I guess. Connect it to a serial or USB, hehe.
However, im still an advocate of using low power. What processor does the Acer laptop have, xhx?