Over the years there have been random reports of
DVC guests being able to pay extra to access the concierge lounges at hotels which offer them. Grand Californian and Beach Club are two that come to mind. However the rates were high and the lounges are not conveniently located relative to the villas. And stories have gone both ways--some people claiming they were allowed to buy a concierge add-on and others claiming the resort declined to do it.
At Jambo the DVC contracts specifically prohibit the resort from selling this sort of add-on, presumably to help avoid overcrowding in the lounge. Only guests staying in those 5 club level DVC villas can have access to the AKV lounge.