Here's a couple of pics of mine, it has a swing down double berth over the front seats so the bed can be left 'made up' and swung down when needed. It is a Hymer which is a good quality German make, but there are plenty of other makes around. I've had motor homes with tha original cab still fitted and the rest built onto the chassis/cab but find they don't have so much room as what I now have which is called an "A" Class type of build.
This site has a menu that will show you typical interior layouts of Hymers, many makes have similar layouts now. The company is the one I bought from, and while they are not cheap, they give a good service and are very helpful. Just have a troll round the internet there are plenty for sale, and the season isn't too far off so prices will go up soon, so you might still pick up a bargain.
Giok