I've been kickin' about a similar thought for a bunch of my buddies and I out here in SoCal.
As of late we've been getting together for some desert camping/shooting trips in some pretty remote areas. Here's a run down on what I've been dreaming up.
My friend's got a flatbed trailer he would lend me to get a car in and out of the place.
Here's a list of items that would [i] HAVE [/i] to be removed from the vehicle [i] prior [/i] to being used as a target:
windows
fuel (drain, then flush tank with water, let dry)
engine oil/tranny oil (drain, flush, let dry)
cooling system/brake lines (drain, flush, let dry)
a/c compressor must be removed along with any traces of freon
battery
drain fluid from shocks/struts
remove tires and secure car on blocks
When done shooting, put tires back on and roll/winch back onto trailer to dispose at junkyard.
I know this sounds like alot of work, but it would be easier to spend an afternoon performing these jobs in the garage than having to clean up the mess it would leave at the shooting spot.
The crew I shoot with usually brings a few Ma Deuce's, some 1919's, a few .50's and a bevy of AR's, AK's, FAL's, and other fun boom sticks.
It would be interesting to see what a few thousand rounds of well placed ordnance would do to a car. [:D]