good idea--look at as many pics as possibe. also look at vintagetrailering.com--he has some amazing dinettes that inspired my build design. it will come down to you and your trailer though as every build has specific needs.
here's a link to my dinette for a 56 BUBBLE that i just got finished last week: http://www.airforums.com/forums/f44/...h-62815-4.html
becasuse the interior has so many different radius's you're going to have to do a ton of measuring, fitting, with carboard then with cheap plywood then with your expensive finish wood. I found that getting my table hardware in first worked well. then you can drop the table down to it's bed position, support it, and take a square to the floor and mark out where your bench supports need to come out to. then figure out your bench side radius to the walls, and build the crazy thing. it's a lot of work--but i like how mine came out. make sure you figure out the heights of your table and seats--before and after coushins as you want it comfortable-- and your back coushins need to be the perfect size when you make it into a bed. plan the heck out of it on graph paper and then start measuring. it will keep you up at night mulling over things for about a week once you start! enjoy--ted