You are correct, this is a constraint of the _JOB data view. Since jobs are account level objects, you'll only see jobs that were created in the account that you're querying them under.
When it comes to _Click, _Sent, _Bounce, etc., these are subscriber level activities. In an Enterprise 2.0 account, subscribers are stored on the All Subscriber's list, which is owned by the top level account. Any of the above activities will be recorded against this unique subscriber record. This gives you the ability to query against these activities across other "OYBAccountID" (Business Units) from the top level Enterprise Account.
You can see within each of those data views that the field name, "OYBAccountID", is available for you to view and narrow down your query results as needed.
http://help.exacttarget.com/en/documentation/exacttarget/interactions/activities/query_activity/