Here are a couple of photos from tonight. I'm not really happy with either one, but looking for suggestions here.
Photo 1
Nikon D70
F/5.6 for 4 minutes @ 10:15 PM
Photo 2
Nikon D70
F/5.6 for 6 minutes @ 10:30 PM
Illumination of both photos: tonight was still a relatively full moon. There was a light cloud layer, so there were no stars out.

In addition to the moonlight, I also used my SB-600 off camera by hitting the test button repeatedly from different points as I walked around the car to paint the car and the background.
Paging Hafid: suggestions welcome for driving cars into the frame without overexposing the headlights so much. Have driven a car through the frame and parked it away from the city lights before? Advice welcome.
Part of the problem for me with photo 2 as well is that I feel I needed a second person there tonight to help out. Since I had to drive the car into the frame and fire off the flash, that resulted in a couple of problems: 1) the car wasn't in the frame long enough and appears transparent in places. 2) the dome light shows up.
Photo 3 (from September)
F/3.5 for 5 minutes @ 10:30 PM
I show this as a bit of comparison. The lighting for photo 3 was provided by a lantern. The foreground and the car's wheels look a bit plasticy to me in this one. I think the flash method did a much better job of providing a cleaner image (photo 1), but ultimately having a night sky with stars out makes a huge difference.
Maybe one of these nights I'll pull it all together, but it wasn't tonight.