I have covered this topic before, but just this week in a conversation about how to quickly create shelter for large numbers of refugees the topic came up again. See this WashPost article: Is shipping-container building ‘the best thing since the brick?’
Here is a link to the earlier posting ( Nov. 2012) about the use of shipping containers for emergency shelters.
Update: one more article from the Guardian on October 9: Living in Steel Box Shipping Containers.
It does seem like a possible solution for sheltering large numbers of migrants temporarily.