great idea, I've contemplated doing this whilst studying (hate being stuck inside all the time looking at the same 4 walls), got a 1000w invertor for the laptop charger when needed (monitors the car battery whist in use to ensure you can still start again) and the mobile hot-spot on the phone for the Internet access . Just need to sort out a table for the back, been contemplating fitting one of the removable one leg ones you get in caravans. Still not done it yet but its definitely on the cards.
Was one bought from halfords years ago Garry, will post up a picture of it for you later on, its nothing fancy, only one single plug point but had a laugh with it years ago when I bought it and had to go buy lengths of wood from a merchants (way to long to fit in the car), out came the ripsaw, in the car park, plugged into the car and cut my wood to length there and then (which then fitted in the car no problem). Had loads of strange looks from the workers lol.