I had a compact sedan for a long time, and can confirm your observation. In fact, it worked best for me to feed the bass into the driver's side rear door (of a 4-door car), scroll first, and then upside down in the passenger seat.

Now I have a little hatchback, and am quite happy. Granted, transportation is still an issue -- I'm floored when I hear about bassists getting around in NYC using cabs, the subway, etc. But it's the only instrument that I play well enough for anybody to actually want me to play it, and I do love the bass.