These are a bit too expensive for multiple bikes, but I bought two of them to use for moving my bikes across the country. Then I sold them on Craigslist.
http://www.aircaddy.com/products1.html
I've packed and shipped bikes using the standard bike box, and while these wedge shaped aircaddy containers cost a lot more (regular bike boxes can often be had for free), they are easier to deal with and super strong. No fears about bikes getting crushed with these containers. They just probably aren't worth it unless you re-use or sell them. At any rate they helped me sleep better knowing that our precious bikes would survive two weeks on a partial load moving van without incident. They arrived in pristine condition.