This is a link to a guide for making a robot base. It looked so well designed and thought out that i had to share it. Contained in the link is a wealth of tips and good practices, also very innovative (and discrete) use of lego components. I learned a ton of stuff just by quicky browsing over it. There are many mini systems he implements can be applied separately into your own setup. (pan/tilt wifi cam, use of microswitches, 3 level power supply, etc). Check it out... http://www.robocommunity.com/article/10915/Generic--Robot--Base-with-RSV2-Attached/