Hey Mike,
As someone with a family of 4 and as someone who just went through the design process with SMB I completely understand your thoughts.
If you go to the sportsmobile.com website they have drawings of the standard floorplans, and there are tons.
Now that said, there is also a do it yourself design tool that is online and more fun than you have had in years.
You pick out the rig..Regular Body vs Extended Body..and then just like the old paper dolls days you move around any range of seats, beds, cabinets or whatever, where ever....not to mention they will flat build anything you can think of.
SMB West is who I have been working with and you should fee free to give them a call or visit the factory for a tour.
They will build your van bit by bit...if you bring in your own van they can do just the 4wd conversion, just the top, just the interior, whatever you want.
Check out the site and come to the Overland Expo in April to see a ton of them in person and if you ask I bet you will be able to drive one at least (mine will be aval.).