I would be shocked if someone had a point cloud already. Perhaps getting vertices from a mesh file is enough? I'm not sure if you're acquainted with CAD tools, but here's a STEP model of the field on GrabCAD you could work with:
https://grabcad.com/library/frc-field-2016-2
If that's not good enough, and you have a lot of time on your hands, you could install FRC Sim and figure out how to add a Kinect to the default robot.
https://wpilib.screenstepslive.com/s/4485/m/23353
http://gazebosim.org/tutorials?tut=r...s#OpenniKinect