The Chief Delphi
White Papers are a great source of info. A couple on drive systems and robot mechanics which I have found useful are:
2005 Drive Systems
Advanced Drivetrain Seminar
This is probably not what you had in mind when you posted your question, but FIRST posted a
Robot Design guide for Vex competitors. It has a whole lot of good tips and brainstorming suggestions which should help any technology team (not just Vex) - but especially rookies.