I think built-ins are always a bad idea. They're generally very expensive, you're taking a big risk on how well the thing will work for you in practice, and in a few years when the next big thing comes along you won't be able to get rid of the old one and replace it. There's nothing that makes cabinetry look more old and tired than an obsolete piece of built-in equipment, and guaranteed it will be obsolete in a few years.
Why not just put in a big appliance garage? Then you'll have the flexibility to do whatever you want in the future.