The quickest way to put together a custom grill area is with a Grill Island. These prefabricated units can be brought in and set up in an afternoon. However they can be expensive and if you don't live near a manufacturer you might get a good sized shipping bill. If you are a do it yourself'er and really want to get exactly what you want then you can build your own with some basic skills.
Your first step should be deciding if you want a gas or charcoal grill. You should also consider what other amenities you might want in your outdoor kitchen. Cabinets, sinks, refrigerators, running water, electricity, natural gas, and lighting are just some of the options available to you. You should think about how much you are willing to spend first. Gas grill heads for top of the line stainless steel grills are only a little less expensive than the full units, meaning $4,000 isn't an unusual price.
Of course you can always build in a less expensive grill head, but a standard rule of thumb is that the grill head should be about a half to a third the price of the entire project. Once you've added up lumber, bricks, cement, wiring, sinks, counter tops, cabinets and whatever else you want to build into your grill, a $4,000 grill head isn't too extreme.
Now you want to look for a location. A grill should be spaced away from existing structures. You might need to check with the local authorities for fire code regulations before you settle on a place. Of course you can build vents and fire-proof barriers around your grill if you need or want it closer to your house or other structure. As a general rule, the placement of your grill should be the same as it is for a freestanding grill. No trees, decks, overhangs or other flammable things should be in range of your grill. A good way to test out the space for your grill area is to take some empty boxes and build up a basic shape where you'd like your grill to be. This will let you look it over before you dig up any flowers.
Gas grills offer you the advantage of controlled heat and features like side burners, rotisseries and lids that allow you to grill almost anything. While charcoal grills can have these same features it may be a little more difficult to get them since there isn't a lot of selection in pre-made charcoal grills that can be mounted in a custom enclosure. However charcoal does give you a more authentic grilled flavor and of course there is something more primal and romantic about cooking over coals. This is one decision you should give a lot of thought when you start planning your custom grill.
Once you have a pretty good idea of the direction you want to go in, head off to your favorite hardware store. Many hardware stores have plans and ideas available for free. If they figure you will be buying materials from them they will go out of there way to help you out. One book you can check out is Building Barbecues & Outdoor Kitchens. There are several project ideas and basic construction information in this book. And, I helped write it. Anyway, a visit to the hardware store can at least be a reality check, so you might be back to the planning stages by the time you get home again.