There are at least a few teams that reuse their crate from year to year. I do not believe that the shipping SIZE requirements have changed much within the last 6-7 years at least. If possible, I suggest building a crate with a hinged door on one side as this makes it MUCH easier to load and unload at your competition(s).
Having the ability to reuse the same crate from year to year elminates recurring costs of time and materials that go into building one.
My high school team (311 Red Jammers) had a welded steel framed crate we used. It could have dropped off the truck with no adverse effects (to the crate
).
Also, remember to leave mounting/rigging considerations in your crate so you can secure your robot.
Unless you want to consider shipment part of an "endurance test" for your robot.