In my unprofessional opinion, the 23ikss is the biggest model Hybrid FR makes.
But as others have mentioned, there are many other 23 so called foot hybrids. The unique thing about the 23ikss is the center island and the double slide. Which can make the floor plan larger than the others. I close the 233s because the 23ikss was hard to maneuver around in while closed and it weighed a little more.
Anything larger and you will be getting into a regular travel trailer or 5th wheel.