Yes 4 kids. 3 in booster seats, one more on the way. the obvious choice is a minivan.
Was brainstorming with a friend at lunch who has a 4th child on the way... what else is there that retain some character, in stock or modified form, but also some daily driveability?
There seems to be a lack of real 3rd row contenders until the current high dollar crossover offerings since the demise of the B-body wagon, which had at least a usable jumper seat.
here's a few that have crossed my mind:
'80's GM Suburban (bagged or dropped on some hot rod inspired wheels):
'90's era Suburbans also are cheap enough to mod within budget but have some more modern amenities, fuel injection, etc.:
the forementioned GM B-body wagons. up till '95/'96 the Caprice/Roadmaster wagons had LT1 power, but even the TBI cars were pretty much workhorses with enough torque to tug them around. Easy to make Impala clones and/or they look slick dropped/bagged. 3rd row jumper isn't a true "3rd row" though so may not be ideal for daily kid hauling:
...the Japanese may be on to something with their modifying Dodge Ram vans:
...and they also brought us the VIP style minivan, which isn't done so often in the US: