Same as the Renault Espace F1 out of Gran Turismo 2, really: formula one engine in a van. Why? Aside from the lulz, it was a technology showcase.
http://i300.photobucket.com/albums/nn7/captain_clutch_kick/supervan1.jpg
The first one was essentially a Transit with a 5 litre Ford GT40 V8 in the middle and really wide tyres. It had 400hp, which doesn't sound much for the size but remember, vans are lighter than cars because they don't have as much glass. This thing could shift.
http://i300.photobucket.com/albums/nn7/captain_clutch_kick/motor.jpg
It gradually became more racing car-esque with Supervan 2 sporting a 3.9 Cosworth V8 and around 540hp.
http://i300.photobucket.com/albums/nn7/captain_clutch_kick/supervan2.jpg
Supervan 3, pictured in the original post, had a 3.5 litre Cosworth HB Formula 1 engine, until eventually for cost reasons that 600hp+ V10 was ditched for a 3 litre V6. Still fast like stuff off a shovel, though the differences between what it will be in TDU and in real life are the real one only has a 5-speed Hewland gearbox and tops out at around 150mph. Plus it might be tricky to get the steering wheel on the right, but we will see.
http://i300.photobucket.com/albums/nn7/captain_clutch_kick/wrc_transit.jpg
Another Transit I may make is this World Rallye version, which, Ford Focus WRC interior aside, has a fairly standard 2.4 turbo diesel, 200hp, and many tourques.
http://i300.photobucket.com/albums/nn7/captain_clutch_kick/Ford_Transit_XXL.jpg
But the strangest Tranny I've seen and one I would like to make (time permitting) is a 3500kg, FWD stretch minibus limo version, the Transit XXL. World's chavviest limo or most luxurious van?