The minimum floor plan on my street is 3500 sq ft. My house is the small one on the street. Only 3900 sq ft. It does sit on 1/3 acre. It is a custom house. Not to my specs, but to the specs of the original builder. Every house on the street is different. All owner occupied.
Sound like the developer really did mean custom houses. Here in California, custom house means the exact same floor plan, they just invert it our put the garage on the left side of the front door instead of on the right.
That describes my old neighborhood in Mira Mesa (north San Diego). Sometimes they even change the colors :-) I left when the customization included gang graffiti. It was a nice house in a nice neighborhood when I purchased it in 1983. I almost waited too long to sell it by 2000.
2nd amendment friendliness was a key requirement in selecting a replacement for San Diego. The endless parade of anti-gun laws from Sacramento was intolerable. Idaho is a big improvement.