You really want batteries bouncing up and down around in your trunk, however so controlled?
How about this...
Mount a battery rack on a pair of sliding rails, controlled by a pair of hydraulic rams, mounted horizontally at the rear of the trunk and facing the front.
With the car at rest, the rams are extended, keeping the rack more or less over the rear wheels. When you start to hop, the dumps for the rack kick in, allowing the sliding rack to 'roll' to the rear of the trunk, possibly onto some sort of buffers to provide your 'hitting' force, this will provide the transfer of weight of the batteries further back from the pivot point.
As the car begins to fall from the peak of the hop, the rams are 'energised' forcing the sliding rack back to over the rear wheels, or perhaps even further forward to provide extra weight for 'downward' force, putting more energy into the hopping coils? A little more controlled than 'jumping' battery racks.
Would that work?
Hot Damn, Good thinking Crystal Cutlass,
This is how it's done, one guy thinks of some off the wall wild idea and others add to it or change it. The before long its mas produced.
Yes it does appear to be an idea too.
Any others??
I just got another one, about using two ID cylinders with a coupling.
I'll post later.