If you want to have a military vehicle which can successfully traverse hilly, rough terrain, as well as high-tail it (stably) down a motorway, compromises about wheelbase length usually have to be made.
Today’s invention offers a new way to think about this problem.
A wheeled digger-type vehicle could be converted to a variable-wheelbase machine by providing it with a set of road wheels which could be easily clamped to the bucket at the front.
Press down with the bucket controls and the front wheels lift off the surface, allowing the machine to move on the bucket wheels and rear wheels only.
Varying the reach of the bucket provides the possibility of changing the wheelbase whilst in motion.
The bucket wheels would clearly need to be steerable, perhaps by rotation of the final link in the bucket arm.