Our users are paired up on every User Story, Defect and Task. We consider both users the 'Owners' of the item. When using the Kanban Board we have the option of just one owner.
Is there a way to include additional users and treat them as owners? Can we see that on the Kanban Board?
The data model of Rally allows only a single Owner to the artifacts/tasks. However, what you can do is create one or more custom fields of type Drop-Down List (User). This field can then be included to your artifact or task. You can even set it as a mandatory field. This field will allow you to select a user who is a team member on your project.
You can then include this field in the Kanban Board and you shall see this user including their avatar.
Note
The actual Owner of the artifact is still the Owner field.