Robot Clearance Specifications

Does anyone know if there is a requirement for the amount of clearance below the robot?

I believer there is a rule saying it may not intersect the field, so noclipping is illegal. Other then that no rules come to mind.

Rules-wise, not particularly. You need to keep in mind how easily you can drive over the scoring platforms (if you wish to be able to do that) and to not damage field elements or carpet.