If I was implementing the 'Pet Store Customer Account', I would set up entity beans for User, Customer, Account, Profile, ContactInfo, Address and CreditCard. These can also be referred to as BO's as they contain state and behaviour. I would use CMP and CMR and local interfaces for all of them, which I would indicate within the deployment descriptor. I would set up a session bean as a facade (possibly with remote interfaces) to access these entity beans to provide data to a client.
IMO the above describes a composite entity for a 'customer account'in EJB 2.0 style.
I would be interested in other peoples views.