Designing a kitchen has a lot more to do with science than the picking out of pretty products, which is what most people think of when they think of "design". It encompasses time/motion studies, ergonomics, psychology, as well as mechanical engineering, building science and building codes. To have a kitchen that works, you have to know and understand all of those aspects of design.

If I were to design an island that would contain the kitchen's only sink as well as the main prep area and cooking zone, I'd start off with the 24" DW, then the 36" sink cabinet. The space between the sink and stove will need to accommodate emergency landing space for the range, prep space, and some cleanup. (We haven't even discussed dish storage, which also needs to be close to the cleanup zone.) I'd want a minimum of 48": between the two. 36" would leave you muddling up your work zones. Then I'm assuming you want at least a 36" range? (Island ventilation is a lot more expensive than wall ventilation, are you aware of that?) And now landing space on the other side for safety. I'd want at least 18" to look proportionate and give you better space for a second kitchen prep zone (admittedly, it will lack access to water and be small, so it will be of limited utility.) Your island size will be 13 1/2 feet, and that does not count on the needed aisle clearance at the ends, which would add 96" (2x 48") to the space needed for this. That means your space needed to accomplish this would be at least 23 feet long. Your 31' is more than adequate for that. However, most people's 12' wide kitchens would not be.

Now take the depth of your island. Your armspan will be around 30" if you are tall or stretch a bit. That means that in order to be able to clean an island wider than 60", you will need to lean and stretch and bend. That's not good ergonomically on your back. Or, you would need to use a microfiber mop to reach the center of an island deeper than 60". You don't often see islands deeper than 60" because it's a bad ergonomic design. Your proposed island is 12" deeper than optimum.

Then there is the standard cabinetry depth issue that makes creating such an island a big space waster. If you use standard 24" deep base cabinets to house all of the sink/drawers standard functions on one side, you can certainly add 24" deep cabinets on the other side as well What you can't do is have 24" deep cabinets with drawers or pullouts if you want any overhang. If you want an overhang for seating, you can use 24" deep cabinets with no drawers, but they will be extremely difficult to access under the standard 15" overhang. And again, your island would then be around 63" deep, not the 72" that you are proposing. To be able to access storage under the island, what is usually done is to have shallow cabinets no more than 12" deep on the back side. Those are still difficult to get to under an 15" overhang, but they are shallow enough that anything stored in them will be easy to find once you bend down. You are basically proposing an island that will have a hard to reach center that will be a void internally and be useless for storage. Make it narrower and it will be more functional, even if that seems counter intuitive to you.

What you are essentially proposing is a galley kitchen with one wall gone. If you study galley kitchen layouts, I think you will have a more successful idea of how to create a functional one in your existing space. You also need to learn how to draw out your space as it exists currently. It can be as simple as a graph paper diagram with all of the windows and openings and utility locations indicated, or you can use software to create your layout. Ikea has a free version that's fairly basic, but easy to use. There is nothing like planning a space in three dimensions to be able to show you what will and won't work. Post your diagram here after you upload it to a photo hosting site like Photobucket and you will receive a lot of helpful layout suggestions.

LWO pointed out the design concerns of the island itself. I would question having a 20' long piece of something in the middle of a room and how that would affect traffic flows. Where in the island would the stove/sink be and is the fridge in the middle or to one end. How far around and from where (eating area, DR, FR, back deck etc) would you have to walk to get to the stove/sink/fridge. Would two smaller islands be a better idea in terms of walk around traffic flows. Is this island going to also have seating at it?

Can you post floor plans?

Thank you for such a thoughtful reply. Like I said I am in the beginning stages of this design. This is not the first kitchen we have done but with each you learn and with each you have new concerns and limitations. I am in the seeking out info stage, (that's why i am here!). We are hoping to begin early this summer.

I have drawn out the design on graph paper and it looks like I may need to go back to the drawing board a bit. We are on a hill with a lovely valley below, that is why the originally designers put floor to ceiling windows on all the walls, I want the view accessible for both the cook and dishwasher (that's me!) and available for the diners.

I will post an image as soon as I can get to it.