I'm curious as to the possibility of using your Mecanums in a situation where accurate odometery is required. For example, on a 50 pound robot, driving forward 10 feet at 1m/s, how much "slip" is encountered on a standard linoleum floor? The application wouldn't be FIRST, but a robot designed for SLAM (Simultaneous Localization And Mapping). Mecanums may not even be feasible for the part, but having some number of slip during normal operation would help.