We ship our robot in a crate designed for medical implements. It's surrounded by 5 inches of foam on all sides, and it's water proof.
It's also Yellow.
So far we know this crate has saved us twice. (it's going into it's 3th year) Nationals last year, alot of crates (including ours) were left outside in the rain. And again, last year, the crate was dropped (had to be at least 4 feet) upside down. We had a tower on our robot that was bent inhalf. Thankfully it was only cheap angle iron, and was only there to support something in the first few seconds. IT was easily replaced.
In the attach picture, that piece of metal is supposed to be a triangle.
http://www.tj2.org/2002/imagepages/p4250187.html