I have seen flush mount built-in USB ports, in combination with 120V sockets and also in combination with the cigarette lighter type connection. Do a search on Amazon, and you will find plenty of hits. As far as your laptop goes, it is all going to depend on the power requirements. I don't think I would hard wire anything into my trailer that is going to be super specific to one applicance (laptop, TV, etc.). Your best bet might be to keep a few of those cigarette lighter ports around so you can plug in a converter. Not the most efficient use of power, but probably the most flexible.