The colors as stated for a designer home are all white, all tan (hayseed), or hayseed with white trim. The two color choice adds a bit over $1000 to the cost as I recall. I am not sure why so much. They will tell you it is because they have to paint each separately. Yes they do the ceiling/walls, but they have to do all the trim and doors separately anyway. They use an oil base gloss on the doors and trim and flat on the walls.
Personally I think the two color choice looks very nice. Go through the models with your design person and they will show you the three choices. You can even go through many of the daily models to get an idea in the various types of homes. Ultimately it is an individual's style and taste.
Just a thought though. If you plan to paint later, and want to go with one color, perhaps the all white would make it easier up front since the ceilings would be white than. That is of course if you don't want tan ceilings with other paint colors
