The solution my colleague provided is probably the best for most scenarios.
As you specified it more and you want to use a repeater, please try the following:
Repeater with Custom Query webpart:
Query:
SELECT CMS_Role.RoleDisplayName
FROM CMS_Role
INNER JOIN CMS_UserRole ON CMS_Role.RoleID = CMS_UserRole.RoleID
WHERE ##WHERE##
Transformation:
SELECT CMS_Role.RoleDisplayName
FROM CMS_Role
INNER JOIN CMS_UserRole ON CMS_Role.RoleID = CMS_UserRole.RoleID
WHERE ##WHERE##
WHERE condition:
CMS_UserRole.UserID = {%CurrentUser.UserID%}
Dave