An E-350 with the 6.8 V-10 could handle that. Particularly the un-extended van, you will have nearly 3000 pounds difference between empty weight and the GVWR. If you do not need seating for 12, you can take out the rear seat, making it a couple hundred pounds lighter. I did that for my van, It took four people to handle the seat, as it is not an easy in and out through the rear door.
You can get about the same capacity with an Express 3500, 6.0 V8 (and the fourth row seat comes out easier). Find one with the Duramax and it boosts tow capacity but reduces carrying capacity.
Generally, you will find that these vans, especially ex-fleet, are not as luxuriously equipped as people expect in SUVs and family-use pickups these days. That's probably why they sell a year old for less than half of what is being asked for a high-trim 3/4 ton pickup.