Lowest Cost: Two rooms at a value resort. There are rooms with connecting doors, but they will not promise them for you unless there is only one adult and five kids in the group.
You can get a King room at a value that connects to a room with two full sized beds. That gives you one room with a large bed and extra floor space for little ones to play, and enough beds for everyone. There is no additional charge for a King bed, but it is a request and not a guarantee.
Next Lowest Cost: Family Suite at All Star Movies. It is slightly more expensive than two standard value rooms, but is the same price as two value rooms in the preferred location plus the cost of a refrigerator and it comes with an adults bedroom, complete with queen sized bed, two bathrooms, kitchenette, and a living room whose furniture transforms into a double and two twins.
Cabins: These have outdoor space, a porch, grill, and a lot more privacy, no shared walls. They have parking directly outside your door. They have a full kitchen (if you aren't on the meal plan then this can really save money to be able to prepare meals). The bedroom comes with a full bed and a set of bunk beds. The living room has a Murphy bed which (about ten years ago) was very comfortable. There is only ONE bathroom, with one sink, and the sink is inside the bathroom. The bathroom situation makes it a deal breaker for our family, but for others it works well, you need to know your family. There is a living room couch that is not a "sleeper" but a child could sleep on that couch.
Campground: On the camping forum there are links to people who rent out large travel trailers which you can have placed in the Disney World Campground. Many of these offer enough sleeping space for your group. It is worth considering. These campers have bathrooms as well as the campground facilities, which in the world of campgrounds are very nice.
Two bedroom villas (Boardwalk) are very nice, plenty of space, King sized bed, queen sized bed, pull out couches, full kitchens, whirlpool tub, and beautiful details. They are so close to two parks and very nice, but we stayed when we were not footing the bill. We just would not pay over $600 a night for the space. Even with 50% off that is steeper than what we like to pay. Every family and budget is different, and if you can swing the cost, it is wonderful.