Git (e.g. http://code.google.com/p/tortoisegit/source/browse?repo=version) and Hg (e.g. http://code.google.com/p/httplib2/source/browse?repo=async2) can support multiple repositories. We should import all of them. I don't know if SVN can have multiple.
Naming might be tricky. I think we'd want to preserve the original names if possible. However, the individual tool import form prompts for a single mount point & label - which doesn't align with multiple (automatically named?) repos being created.
I feel like the individual tool importer should only import a single repo, but allow you to specify which one. The project importer should pull all available repos (excluding wiki).