Does this floorplan exist? Queen / dinette slide / cabover

I echo what others have said...

The Sprinters don't have a lot of payload left. More/bigger slides = less payload available, which may not leave enough capacity for a family of 4.

Also, beware that the seats in the living area of any motohome will not be near as comfortable as OEM truck seats for long drives. Being able to get up stretch is the only saving grace, but I'm not sure you want kids up an about while driving.