If your husband is insistent on a 4 car garage, then look at making the garage rear entry instead of front or side entry. It wouldn't look like a commercial auto repair place with a small house attached then. It would also give you the turnaround space as a private "party" patio without having to construct an extra patio. It will only be minimally more expensive for your driveway paving to construct it like that and it keeps the facade looking like a house at least. You will have to have a large enough lot for this, but if you're looking at a 4 car, you're not looking at 50 foot wide lots. Our workshop/garage is side entry and the single and double doors are basically in line with the house's side entry garage. Like all side entries, it's at least only partially visible to the street. We've had the "auto shop attached to the house" comments, even though the house is in front and they are separate structures. We had to do the shop in the rear because of codes, but we have a great view to the rear of the property, so building it in a "L" orientation to the house was our compromise to keep as much of the view as possible and still have the shop. I only wish we had had other more aesthetically pleasing options. Starting from scratch gives you a lot more options.

www.google.com, that should have everything that you are looking for.

You should build the largest garage you can fit on the property. It will get filled up. I know lots of people that use their garages only for storage. You can never have a big enough garage. We built a 24'x24' garage for our previous home. It really was my garage and my husbands shop. With things in it his full size Chevy truck was tight so he never parked in it. We also have 3 motorcycles that we stored in an enclosed trailer. Our new house has a triple garage with one small and a double door. At only 21' depth his truck still gets parked outside. Our motorcycles are in the smaller side and my small car is center stage in the larger. If he were to park in it he would need to close the garage door after walking around the back of the truck. His truck does have a large grill guard that is the problem. But he has plans on building another garage that is 27' deep for his truck and projects.

You should have an engineer to inspect everything leaking or not to make sure the structure is structurally sound especially with basement being under the garage.