RVs with extendable side 'rooms' .

[swordtart]

Since these can only be deployed when stationary and the main purpose is to provide additional living space (to move about in) you would also need to consider the loss of utility of those sides.

An easier way of looking at it might be to modify Passenger Accommodations. When stowed the side rooms take half the space required for Passenger Accommodations. So you could have a single berth which would only take up a single cargo space when closed up but opens up to a standard single berth.

The additional flexibility should double the price, but the weight needn't be significantly different if the rooms are operated manually (taking 10 minutes the crank into place and to recover). Alternatively a motorised system ($500, 100lb, 1 spc, 1DP) can be installed that will deploy and retract it automatically in under a minute.

The fact that the vehicle will be undriveable until the rooms are retracted is a sufficient balance in my opinion. If you are caught with the rooms deployed the fight will be over before you can retract them.