Diesel is the way to go if you don't mind disconnecting speedo's etc.
I'll be looking at the later model L400 Mitsi Vans which are 2.8 turbo diesel if/when I can get some cash organised.
Plus they are walk-through from front seats to rear compartment which is better than having a bloody great engine cover between the seats.
You can pick them up from $3K to $6K and they come with enough removable seats for your tribe.
The vans are pretty good in 4wd too. I've not had mine stuck. At least no so stuck that I couldn't get myself out.
And of course, heaps of room for sleeping/cooking/camping etc once the seats are removed.