Some people choose to construct their BBQ Islands out of cinder blocks and others use steel studs. Both have their merits. If your island has curves in it then cinder block is the way to go. If you are trying to maximize internal storage space, steel studs are the best choice. The main thing to remember is that the spacing of your components is critical to your BBQ island's usefulness. As long as you are purchasing medium to high end cooking components, the spacing of the equipment is probably more important than the actual components. If you can't set a plate down next to your grill, you will be unhappy with the finished product.
Building a BBQ island this size allows you to incorporate a large variety of cooking and entertainment components. Ice maker, keg chiller, side burner, a/v components, griddles, seating for guests. I could go on but you get the idea. Have some fun with it! We highly recommend the built in pizza ovens for this size island since it is a huge ambiance setter and aesthetically pleasing. If you are planning to do a built in Kamado smoker keep in mind to create a drop down shelf to set it in, also have areas open for wind to get in and cleaning. These are a little trickier to do so we recommend doing your research first.