I suppose if I could let my imagination run then I'd like either a fully tracked or half track type of truck.
However , leaving my fantasies aside and returning to reality then I'd look at a 6 x 6 petrol engined vehicle being at best something of a thirsty beast and as such perhaps not the most suitable vehicle for everyday use.
That said a 6 x 6 Land Rover can be gotten and could serve as the basis for a conversion. There's also the possibility of converting one to look like a historical military vehicle and then renting it out for film or TV work , should offset the cost of the thing a little.