Wow! Both of you have raised amazing points!!
Ahmed, thats a good point. Here are a few things I would like to clear:
1. Yes, ports can be a problem (Refresh: 1 PP, 1 Serial rs232, 2 USB), but I wanted to include something very vital in the project. Similar to the lines of what ash pointed out. I will talk about it in the end.
2. You are right about the weight, but we can try our best to strip it down. It uses a P1 processor. 128 MB RAM. Still have to see power consumption. As ash said, we can keep the VGA-outpt and remove the screen. I also think, for some field jobs we need good traction, if its okok light then it can slip off surfaces and be a bit ... flimsy. Dont know, lets see. From robot competetions I have seen on TV. A 200 lb (about 90+kg) can run good on affordable batteries.
3. Above
4. Customization: Another important factor. But what does the laptop replace? Only the mC. Still we have the motors, sensors and the power management to handle. Well, we have the most flexibility with a powerful processor with
"INFINITE" inputs 
This is the fun part, the processor and the inputs!
See next post on Processor and Input/Output.