I have been following Marmol Radziner Prefab for years now. Unfortunately, the idea has been severely impacted by the economy. However, as I am sure you know, the houses they have built are terrific. http://www.marmolradzinerprefab.com/
The other initiative that is very interesting is Living Homes. The best ones have been designed by Ray Kappe who was a draftsman in the studio of Richard Neutra. http://www.livinghomes.net
There is urban praxis for code compliance in modular construction depending on the city. (house moving has been going on for a very long tim).
In Europe there is Huf Haus which is a long established company comparable to the American Deck House. These house use factory cut timber and on site construction. This semi-modular approach has been around for awhile.
Dwell Magazine has been on the forefront of pushing this concept and they have collaborate with most of the manufacturers.http://www.huf-haus.comhttp://www.deckhouse.com/the_dwell_home/default.cfm
While we are on this topic check this out:http://www.airstream.com/products/2008-fleet/travel-trailers/international-line/ccd-signature-series/index.html