there is no perfect dimensions for an island. Try to organce space subdividing into smaller cabinets of 60x60 cms which is the max space for a structural division and works for seating area as well

You should be able to get everything that you want ........ Are you going to have a cabinet maker build it for you ? I suggest that you work with them and have them draw it up for you........Most cabinet makers are very good at working with their clients to get them what they want.

This reminds me of my kitchen in Hyderbad, India. As others said, go with open shelves. Both wood (contrast) and stainless (brightness) would work well for upper shelves. I would also do shelves in the lower cabinets. If you want to minimize cleaning, add heavy, easily washable curtains to the lower shelves. You can add some battery operated lighting so you can see into those darker spaces. As for the walls, I would use a white subway tile and go as high on the wall as you can afford. The glaze will reflect more light and the surface will be relatively able to keep clean. Paint the other walls in a high-quality white paint (use a ceramic one if you can find it, as they are a lot more durable). Keep the appliances to a minimum. Kitchen gadgets might be handy, but lost of them will make the space seem small. For the ones you do buy, go with white or stainless steel. Finally, hang pots, pans and utensils on the walls to free shelf space and get them off the counter. Make sure what you use frequently is within easy reach, while "occasional" tools can be higher up, where you might need a stool to reach them.

add some pictures of your space for better suggestions