A web site like this is about as close as you're going to come:
Click here.You can see a listing of all the different brands of RV and their manufacturers, but you still have to drill down into each web site for the details. But, once there, you can always book-mark the floor plans or brands that interest you, then compare them after searching (a few hundred or so :? ... well ... a few anyway).
Next, check your local area for the available dealerships, then take your list and actually go and compare apples to apples.
There is no single consolidated site anywhere that I know of. But the list on the web page I referenced above, is about one of the best for consolidating all the brands and manufacturers.
Good luck.
