It's kind of driving a tack with a sledgehammer, but the other options I'm aware of would be a custom CRUD program, and/or spending as much, if not more, time making a major CMS work, unless somebody knows of something else that amounts to a multi-client Access DB system

. It definitely does support CSV import and export, including with custom fields.
It could be done with a CMS like Drupal, FI, but external data importing tends to be a pain, IME, and you'd likely end up spending hours in Views to massage it to your liking, after you use feeds to import it--and that's assuming you won't have the learning curve of just getting Drupal and up and working. OTOH, more blog/gallery-oriented CMSes like WP or Joomla, you'd have to spend your time elsewhere, to make it not so annoying to use.
Ready to go VM, to at least see if it's easy enough for such limited use:
http://www.turnkeylinux.org/vtiger