I have been looking for an answer to this question for over a year. In my case, I don't have enough height to use an overhead door. I have been priced over $3,000 for a pair of doors for a 6'8" by 8' opening. That does not include the jamb or installation, nor does it have gold inlay. My hope is to use either cypress or PT pine for the framing and cover it with 3/4" cedar vertical siding. I would guess some sort of Z-buck or mortise/tenon would be needed for stability. I don't have the proper tooling for mortise/tenion but would be willing to hand tool it using drills and chisels. I have a drill press and believe that an attachment is available for the mortise. I could use my table saw and compound slide saw for the tenon. Given that, is there any material that would guide me through the necessary steps? I might want to include a small amount of glass at the top of the doors. I have a lumber mill nearby that can provide the cypress for framing and someone who would run it through their planer. Thanks for any suggestions and I don't think I hijacked this thread but rather added to it. I agree with the poster that most are on the West Coast, although I found one in PA, where I live, but the price is off the charts.

We did an 8 ft door, figured what's one more door. Aesthetically having them all the same height makes sense, especially since how it looks is the only reason for 8 ft doors in the first place.

I would place them as close to each other as possible. I would do only one stick of trim between the windows, so it's 4" and not 8" of trim (4" trim on one window + 4" trim on other window). If that makes sense? So, give the illusion they are mulled. Then 4" trim around the entire unit of windows.

You might also want a "people" door from the garage to the outside, ... perhaps between two 12' doors, so you'd want six feet in between the two 12' doors and another six feet at least one each side. ... perhaps alongside the house between house and car leading to ?back? or ?front? door ... in which case you need to allow walking space for that. If your garage will have your cars parking with the house to one side, then, budget and lot/landscaping/driveway permitting, of course, something else to consider might be to add a back door to one of your garage slots so you can literally drive all the way thru as if it were an open carport. On that kind of garage (that could have a drive thru feature, whether or not it does), something else I like (but have seldom seen), is to have a small unheated breezeway between car and house -- a small "room" between garage and house with a window facing the front and a door facing the back -- both with screens -- and a ceiling fan or two. That breezeway doubles as a space for a door from the garage to both the house and to the exterior without going thru the house or making room for a second "people" door to enter/exit the garage AND it enables you to have a space to catch/remove fumes and smells from the garage before they enter the house. You really don't want either car or lawnmower exhaust in any part of the house, even the mud room. It is also a place to park a bike or two or a leaf blower or snow blower or hooks for heavy wet coats to enable them to air dry before bringing them into the house.