Hi Melissa!
As with everything else, as your family grows your budget seems to have to grow as well. Walt Disney World appreciates the needs of the larger family and has tried to improve the accommodation choices for those with five or more.
There are options for a resort for a
Family of Five or more in each category, Value, Moderate, Deluxe, and Villa. Although booking a family suite at the Art of Animation or All Star Music will be pricey your only other option at that level would be to book two rooms and hope to get them connecting to each other. Having the larger suite area is nice and keeps everyone together.
The moderate category can offer the
Cabins in Fort Wilderness and that is an excellent choice for a larger family. The bedroom has a queen bed and bunk beds. The living area has a queen sofa sleeper. There is one large bathroom, dining area, fully equipped kitchen, and deck with picnic table and grill. Each cabin is completely separate giving you privacy unlike any other resort. Full maid service daily is included and full resort guest amenities apply. Some of the other moderate resorts such as Port Orleans Riverside can accommodate five persons but the room will be quite crowded. These rooms are only in certain sections of the resort.
If the budget can handle you might also try one of the DVC properties. The two bedroom Old Key West unit is incredibly spacious with two bathrooms and two bedrooms and a very large living , dining, kitchen area.