Last time I was in Cancun (last May) there were Taxis available that were more like large vans. You shouldn't have any problem getting a ride. You might want to make arrangements before you arrive. I just needed a cab for two so it was no issue at all.
FYI, it costs ALOT more for transportation from the airport than from PDC back to airport. Our taxi was $120 US going and $40 coming back. Same car!
Go figure