If you are as cautious as i am, you can make a door adapter. Which serves the same purpose if your goal is to get exterior out of the car. Well my design is based on a design i saw on the boards few months back. It is u shaped bar with rubber coating that slides on the door with pressure (of course with the window opened) and keeps your camera semi-indoors. One thing i would do is secure the camera to something inside the vehicle. You could also bust out with some of those padded bags sheesh what is the name ? Video bags or something in that genre. Anyway make sure that camera is safe and secure when flying at 60 mph.
I have made many experiments and spent time on the DV car mount issue in order to come with a good new product.
The main conclusion was to drop the Vacuum / suction cups option. Today’s cars have many curved lines that make large diameter suction cups unreliable for long term (Hours) mounting, The smaller and chipper vacuum cups are not reliable enough and are misleading, One minute you think it holds firmly and the next moment it losses vacuum and your camera just drops and flies away.
Car Hoods and dark cars body gets very warm in summer and have impact on the reliability of the vacuum holding power, Most pro users secure the vacuum rigs with straps and hooks, They know why.
So I have decided to go for systems that use more reliable and robust mounting system to ensure that the mount and camera will stay firm in place and be safe.
Vacuum cup mounts are good only if you really know what you are doing and take all precautions with them.
We designed a very nice CarRig for DV users that will be launched at IBC Amsterdam in September.
for cheap solution you ca use bysicle mounting system and steady bag inside , its quuit easy to rig it ,you can add some hevy metal rod on the mount and hook the camera on monfroto or similar magic arm , something like that was desighn here by one of dps , its working wery nice and we shoot with dvx with out any problem
the problematic issiu is to rid from the sky reflection on the front window
you guys are really over paranoid... Use some suction cups and use some safety straps, I use car mounts often and never have a problem. The suction cups have a warning system that lets you know far before when suction is being lost.
Magic arm alone is ok, but your footage us gonna be very very shaky.
As for the sky reflection there is no issue really, use a polarizer and flag off where the lens is like I did here last week: