Here is the new cart we made/had cut. It just got back from the powdercoaters so it's currently pieces in the corner. It'll be put together this weekend. Dimensions are 30" wide, 40" long 16"tall with a 48" tall handle that's removable and storable in the bottom tray(A la 148).
The top sports arrays of obround holes and custom made wheel clamps that slide and adjust to any size/location of wheel for any year. This keeps the robot firm.
The bottom tray also has a few hundred 1/4" holes in it. This makes it extremely versatile in terms of adding things later(Battery mounts etc would rivet straight in), but will probably support a nice mat right now.
Btw it looks great in Black B)