My buddy has a Model A pickup.

I've driven it short distances with the whole body off. Milk-crate lashed to the frame to sit on, and nothing to hang onto but the steering wheel. Not real smart.

We drove that vehicle a lot before the windshield went in, including a few times that it was snowing. He never got around to putting the whole interior in, but there isn't much to it in a Model A (just inside door panels, really), nor did he bother to put a windshield wiper in for several months. He couldn't get a speedometer, either, so we just guessed how fast we were going, or clocked it with another vehicle. (For the record, 50 mph in a 35 with no windshield in a vehicle with lousy brakes is fairly exciting.)

For some portion of the above time, the vehicle was also missing it's license plates and insurance, and it's inspection sticker for most of the time he drove it.

He's redoing it again now, so I suspect we'll be getting back into the phase of driving half a car fairly soon...

EDIT: Just saw the bit about problems with cops. Ironically, the only thing the cops have ever pulled him over for (twice) was the missing right taillight, which the car wasn't orignally equipped with and therefor doesn't really need to have.