Usually, current or a vehicle age . I am sure that if there is a Jeep Liberty you can get , but you're limited to what they have on the site.
Not sure if I'll let test drive, would not hurt to ask , though.
If you have your own insurance , cheaper is to use that ( make sure you have collision and comp , and that his insurance will cover a rental vehicle) . If not, call your credit card company and see what kind of coverage they offer. Or, ultimately, purchase insurance from the rental company. You'll pay good money for it, though.