I too think you have a nice system. Given your room size, I'd be careful about going with a large full-range speaker, it could overload the room in the bass and you'd lose the flexiblity you have with the separate sub to control the deep bass level; if you like the JM Labs speakers you have, the next size up might be a good choice, but make sure it works in your room.
I'm not sure what you mean when you say the REL doesn't have the full range sound. Where (at what frequency) do you cross over to the subwoofer now--perhaps lowering that crossover point will help?
I'm not sure what you mean when you say the REL doesn't have the full range sound. Where (at what frequency) do you cross over to the subwoofer now--perhaps lowering that crossover point will help?