Multiple Ubercart Catalogs vs Multiple Drupal Installs

I'm starting a couple of new websites very soon and initially we have been looking at using Drupal once again to handle everything.

On the first site, its a simple catalog of services with prices quoted, but no actual checkout required - just an email to staff in the office telling them to contact the user about his order enquiry. That should be simple for something like Ubercart, but the spanner in works is that each customer/company will log into the site and see a unique product catalog for that company, complete with different product descriptions, images and prices.

My question is can Ubercart support multiple categories to handle this, or am I going to have to create multiple installs of Drupal each with seperate installs of Ubercart?

Fortunately this is only required in a single language and currency, unlike the second site... but I'll leave that for another day!

Any help or advice gratefully recieved.