In searching for precedents, very seldom have I ever found much that corresponded exactly to my topic. So, in that spirit, I offer the following: Rossi's Teatro del Mundo; Lou Kahn's floating orchestra platform; the Queen Mary, Titanic, and any number of other liners which had to support and entertain 500-1500 people for weeks at a time; Archigram's Walking Cities; Superstudio's Infinite City-scape with plug-ins; riverboats of the mid-1800's; the Situationists' critical city overlaid existing cities'; the NY prison barge which operated in the '80's; Corb's Unite d'Habitation (a few of them: Marseilles, Berlin...) which were intended to be somewhat self-sufficient and sort of recalled vessels in their forms; the space station; Shigeru Ban's temporary city structures for refugees; circuses and carnivals; pre-Columbian Native American communities; gypsies over the centuries in the middle of Europe...

Obviously each of these will give you different takes on what a nomadic community could be and what issues it will face. While none are exactly transportable modern cities (except the Archigram fantasies) they each can suggest themes that you could explore. Will you look at their function as communities, their relationship or separation from 'place', their technical aspects which allow demountability, their 'separateness' in relation to the conventional city (Foucault's Heterotopia), etc.?

For theory, Heidegger is always a good place to start: my undergraduate thesis explored the possibility of a project with no fixed site which still responded to the pressures and characteristics of a community-at-large. Heidegger (one of the essays in 'Being and Time')considers the unique potencies of 'place', separate from a site's dimensions and specific physicality.

there is kansai airport in japan
http://archinect.com/news/article.php?id=P6651_0_24_0_C

and then there is this whacky thing: Freedom Ship
http://www.freedomship.com/


not much help i know but in the 2 seconds of time i have ....