Have you folks considered using a Maruti OMNI van. I've seen it being used for a lot of light Cargo duty - Couriers, Parcels, School Bus, Delivery Van etc.
It's got loads of boot space. Get rid of all seats except the Driver's, and you have a lot of area to play with, without having to modify the vehicle (important from RTO issues).
The two side doors slide out, making it better than either swing doors or gull-wing doors.
And the rear boot opens up too, like a gull-wing sort of way.
Old one's could probably be available for cheap.
If we know people who can reach out to Maruti and get them to sponsor a Van, that would be killer.