Multisite design for an exhibition

Hello,

this might sound a very open and vague question but I try to be as specific as possible.

I need to design a website for an exhibition that will be centered around four $Countries (initially). We would first insert some content ourselves but then external users (virtual visitors to this exhibition) must be in a position to upload extra content that will have to be displayed accordingly, e.g.: a user could upload a $Picture, a $Story, a $Video, a $Song, etc. of his/her country. For every $Object there should be then a browsable database. The type and number of $Objects is defined.
At the end of the exhibition this same website will be managed by a local association and they should have the ability to add extra $Countries etc. (not extra $Objects)
The exhibition will move from one $City to another and as that happen a new website for that $City (same site under a subdomain or subdirectory) will be created.

Because WP is pretty much everything I know about web design, I was thinking to run a WordPress Multisite installation with separate sites for the various $Cities the exhibition will visit. Every city-site should have an upload form for the various $Objects ($Pictures, $Stories, etc…).

Now to the questions:

– is it practical to develop this under WP or are there better alternatives?
– how would you manage the different objects? I was thinking to use different taxonomies for the objects (users submission will turn into posts) and category for the countries but I’m not sure this would be ideal… what are your thoughts?
– I know zilch about Buddypress: is it something I should consider for a project like this?
– I need to aggregate information on the top level site: would you install WP MU in subdomains or subdirectory? What way would you chose to aggregate all the information coming from the various underlying blogs? RSS feeds?

Thanks for your kind replies!

Matteo