You were refering to this image:
http://wendyusuallywanders.files.wordpress.com/2008/12/containerhome.jpg
Sorry the image tool is down.
Several people have said this would be too hot and that it would need insulation. I agree if it was placed in direct sunlight, but this could be dealt with on the short term with a cana thatch over roof and by planting trees and other growth around the unit in the long term.
I think of something like this for regional access points for aid. You need something that is secure and being semi-portable would be a plus as well. I live in a 8x12 shack with a tin roof for months near the equator running a small store out of it and it never got hot as long as it was ventilated.
You can also use the heat absorbtion of metal to create a chimney effect to pull air through the building. Put a layer of corrugated tin painted black above the unit with a sealed air space below it and a vent on one end of the building and possibly a chimney. The sun heats the space inside to a higher temp and as it rises it is released through the vent. It pulls cooler ground air through the building through an opening in the inner roof on the other side of the building. It is completely passive and only works when it is hot enough to create the draft.
There are about a million shipping containers lying around in the US. Much of the aid will be coming to Haiti in these containers and converting them to housing would need minimum labor. For the cost of returning the containers thousands of homes and other buildings could be built.