NOTE: this is a quite old post and in latest revision some construction details maybe changed
Before to start this task I print the bottom plate design, using CAD software, on A3 sheet with 1:1 scale factor. I glued this sheet on a 400x500 mm plate made of fiber glass is a sandwich between two sheets of carbon fiber.
I start cutting the plate using a Proxxon small driller (http://www.proxxon.com/en/micromot/28472.php?list). Using this tool was quite easy to cut the plate: the only problematic parts was the slot for wheels (specially the rounded corner).
After cut the plate is time to drill it. This task must be done with high precision in order to match mounting for motors, boards and sensors.
Using the same Proxxon tool with a grinder I finish the border of the cut plate to make it smother. After this task the glued paper and the protection film from the plate can be removed.
Here the final result with motors, wheel and board mounted.