This topic has kept me up at nights. Like you, I hate using a big oven when a smaller one will do. So, I have decided on a speed oven--likely Miele, although GE and Electrolux makes them also--which is a microwave, convection oven, and I think/hope it toasts as well. They are a little less than a half-oven. I would go for the wall oven, warming drawer, and toaster oven/speed oven for you, and skip the double ovens. I think double ovens are great if you bake in large quantities where the food needs to be precisely cooked at different temperatures, but for meats and potatoes and such, the temperature differential is not really a big deal. It is easy to reduce/increase both the temperature and time and still have everything come out fine. A warming drawer is fantastic. Remember, with a convection oven, things cook faster, so for that occasional large meal, it is easy to cook many things and as they finish, put them in the warming drawer while you go onto the next item. Also, with 6 people in your house, you will have kids coming and going at all hours of the day. Rather than say, "Honey, let me heat up dinner for you," you can relax on the couch with a glass of wine and say, "Honey, your dinner is in the warming oven."

The oven part of speed ovens is convection. A fan which blows hot air. Some also have a broiler of sorts or some other form of top heat. It might be out there, but I've never heard of one that has a bottom heat feature ("traditional oven"). Same for combi-steam ovens, so don't let that idea lead you astray. Some baking works fine in a convection oven. Some does not. Breads and cakes are probably best. Pies, probably. Cookies can be done but the reports I've seen are about a dozen cookies, not a full sheet. What speed ovens do is SPEED. If you don't have a desire for combination oven and microwave cooking to speed up the results, a speed oven doesn't make much sense for what you've described. You can get a smaller traditional oven, and put a little countertop microwave out of your way somewhere for the few times you want it. I use the microwave part of my speed oven on a double portion of lasagna I've frozen when I want it fast, but it's better reheated in a regular oven. What SPEED is good for is cooking a whole chicken in half the time. It's still not as good, in my opinion, as the long way in a regular oven, but it's fine, and if you need to get the family to the table and out the door fast, it's an option. That's what the raves here have centered on, or baking a potato that tastes baked rather than zapped in a short time. Any oven can reheat lasagna well. It's one of the easiest things to freeze and rewarm well.

This has been discussed before. While my CSO is by far my favorite thing in my kitchen, it is not a substitute for a regular oven. I would encourage you to keep an eagle eye out for a good deal on a basic wall oven from Bosch, of KA, maybe even Frigidaire. You will not regret splurging on this appliance, but it small and a regular oven will be absolutely expected for resale (which would be hard to add as a pst minute thing considering the cabinetry, etc.)

@CPArtist, Thanks for your input! Again, I put up the layout for fun (since the original is, really, interesting/unusual). This will be the 6th kitchen we've designed--we know that it probably won't look like the average American kitchen. We've had the trash near the sink, and much prefer it in the island, where the vast majority of cooking scraps end up. We've also had wide aisles, and find that we prefer what we're used to, which are admittedly not what most people suggest. Too wide and we feel it's awkward. It's yet to be a problem for resale. To be clear, also, the design rendered above is my 'sketch,' not what the contractor etc are using to actually build and design. It is a general idea. For how we live, and cook, it's much more functional than the original with the stove facing the opposite way with air behind a false wall. Again, thanks for your suggestions! If you have any experience with a 24" oven that you loved, I'm really looking for opinions there.