Backup bass with shorter overall length

Here is the situation.

I am wanting to get a backup bass for gigging that will fit into the trunk of my car. I currently gig with either a 4 or 5 string NYC Sadowsky and while it fits across the back seats in my Nissan Leaf, it doesn't fit into the trunk, so I need to go shorter. Plan is to be able to keep it in the trunk during the gig. Chances of needing the backup are super-slim, so in a worst-case I have to run out to the parking lot. Not concerned about theft, etc. the car has a cargo cover. Secondary perk is having an overall cheaper option if I don't want to bring the Sadowsky out.

I am basically looking for suggestions in either a short-scale instrument, or a headless instrument. For argument sake let's say keep the suggestions below the $1K mark. And while I don't expect this instrument to measure up to my regular players, I don't want it to be too crappy :). I am fine with it being a 4-string, but ok with 5ers too.

Later
Rob