Almost all manufacturers make a rear living arrangement in one length or another. They are as common as fleas on a dog.
I suggest going to your nearest RV dealerships, several if possible, and scarf up all the brochures you can carry, it will give you a lot to ponder and unlike the computer you can lay them all out on the table at once and compare different MFG's floorplans at a glance.
Then with the brochure of the plans that appeal most in hand go visit them in person.
Then start looking on the net for good prices.