Campayn does have a multi-user account!
Here are some of Campayn's multi-user account features:
All users sign up under the main account that the owner sets up.
Owners can assign any users as admin.
Owner/Admin can grant or deny access or delete any user.
User can share owner's account or pay for themselves.
Owner/Admin can share templates, images and articles with users.
Owner/Admin can login as any user
Reset passwords for users having trouble logging in.
For further clarification, the Owner account doesn’t share his contact lists, only the contact limit. If the Owner has a contact limit of 10.000, he can distribute that limit to his sub-users.
The sub-users need to import lists individually.