Some Ventures for the 2004 model year have one single child seat built in as standard. However depending on the model and/or how it is equiped some don't. You would probably want to confirm this with whomever you are renting for before you go.
We rented from Avis in November to drive one way to Port Canaveral and another one way rental back to MCO.
Both Ventures were set up with 8 passenger seating and had a built in child safety seat. I wish I had known it before we went, would have saved hauling her booster seat!
Thanx disneyeveryyear! We have the same itinerary (MCO - Port Canaveral - MCO). Was the child seat in the 2nd or 3rd row of seats? Thanx again for your help.