It would be interesting and cool if Smart created a van similar to the one shown below using parts from the Fortwo model. Since they don't seem to be very smart in running Smart (IMO - otherwise they would still sell the gas powered Fortwo in Canada and the USA since the Smart ED does not have a lot of appeal or range [this is just me letting off some 'steam' and frustration]).
Here is the Smart Fortwo (model 451). While one cannot see it, the radiator is in front with the engine / transmission is in back.
This is the air cooled engine Volkswagen Beetle. Since the engine does not require a radiator, there is more space in front for cargo.
The Boonie Bug plans can be bought at R Q Riley. It is made to fit onto the platform and parts from an air cooled Volkswagen Beetle. There is more information of it at the site of the plans plus photos.
To use the Smart Fortwo engine, one would need to create a front where one could place the radiator. Unlike the original Beetle engine, the Fortwo engine is water cooled. Since it is made from plans, it might not be too difficult to adapt it for a radiator (not really speaking from experience but just my opinion).
I think it would be only slightly longer, wider and taller than a Fortwo. This comparison from what I have seen of of the Smart Fortwo and the Boonie Bug (not seen together and without comparing the size of either vehicle).
Since the (it seems to me) Smart Fortwo engine is more compact than the Volkswagen Beetle, it might not need a bulge in the back like this (from what I can see but it might need it when actually done).
It was used in the movie Total Recall with Arnold Schwarzenegger.
This is a site with a diverse set of plans for a variety of items.
I believe this is the international site for the company.
a work in progress
needs work but is still good