The Top Building, (Hugh Building, With a Double Garage), took me one Day, (My First 'Hugh' Building), Its Dimentions Are:
Width = 200
Lenth = 100
Height = 35, (10 Per Floor)
Garage Height = 15
Most of the Time is Taken Drawing What the Building Will Look Like First, Then Changing it After, IE, AddingRemoving WindowsDoors, Texturing, Ect
I've got plenty of Small Buildings in my Map, But I Still Want Some Large Buildings to Use For Missions in my Game, So I Don't Mind Taking My Time on them.
The Second Building, (With Raised Extention Thing), Only took me about an Hour to get that far, But it has a Balcony InSide Which Took most of the Time.
Edit: and I Don't Think 10 to 30 Minutes For a Small/Medium Sized Building is that bad though...
The Attached Building took 5 Minutes, and I Don't Think I could make One Any Faster than that!!!
Dimentions = 95x50x20, But When you Load the Building, You Can Change the Scale.