In this article I want to highlight only the possibility to sleep in the SUV, because a bigger focus is beyond the scope of a single article. There are so many options that it is just to much to write about: there are still the other vehicle formats, vans, pickups, trucks, sleeping in a roof tent, folding roofs, pop-up roofs, caravan fittings, Trailer, simple tents, which vehicle choice as such, and much more...
Even with the off-road-vehicle choice you will define a lot about the available space.
In most makes of the internal height is not sufficient to be able to sit comfortably at a table inside, but there is always a way to at least plenty of storage space and a nice deck area to create a kind of minimal expansion sleeping area. Maybe these samples and links helps you to find a good solution for yourself.
Always try to see the advantages and disadvantages of any setup. You have to sort out some of these solutions because there are just too many.
Depending on the vehicle length and the square of the front seats must be taken in fitting, ie, the seats must be folded to the front / rear to get a decent sleep platform.