I found this:
The Wedge bar
Product Overview:
“The Wedge Bar” is an in-car camera mount that mounts between your cars headrest bars. It can be positioned in virtually any direction or angle. For example, it can face forward, backwards, directly at the gauge cluster, boost gauge, or in any other position one can think of.
The product’s mounts are fully adjustable based on how high or low they are positioned on the seat posts. With the turnbuckle design the bar is very quick and easy to install. You simply get the mount close to the length you want, slide it between the seat posts and spin it up until it is snug. Then you lock down the locking nuts and mount the camera.
The mount is universal due to the fact that all cameras today use the same thread for their mounting point. The middle portion of the bar is made out of a non-smudging material that does not leave fingerprints. The bar also is very light, weighing less than one pound at 14.6 ounces. The range of The Wedge Bar is 17 ¾ in. or 45mm all the way out to 32 in. or 81mm. As long as your headrests bars are within this range The Wedge Bar will fit.
On slowboyracing.com website but $99 that seems a little high as usual with their prices, is there anywhere else to order one and who is using one already in their car?! This is going in my '91 eagle talon.