I'm sort of partial to a U-shaped dinette myself, although i do understand that it reduces table space and the inner seat(s) are hard to get at.
The reason I like it is the corners make for good chaise lounges... A U gives you two, while and L gives you one.
In our old popup we had what they called a gaucho.... basically one of the dinette benches extended to span the entire width of the back wall, then wrapped the corner coming forward a bit. That was the best seat in the house.
Granted in a larger class a you could have an honest to goodness flexsteel or lazy boy type chair... but if you want a dinette....
If I were faced with the OP's question, and needed a dinette with banquette seating instead of a table and chairs, I would very likely just build my own. It's really nothing but a plywood box with some cushions thrown on. That way, I could consider ways to customize by optimizing the back rest angle for best comfort, custom located drawers or cabinets, etc.... then any upholstery shop or even a friend with a sewing machine can make up some simple cushions if you yourself are not so handy with a singer....
