What is considered to "protrude dangerously from the car"?
Is something a la this acceptable?
http://rennline.com/interior.php/sid/3/aid/8/nid/9

I'm not a fan of the strap method (how would it not pull the bumper cover off?). That method or a trick collapsable D-ring setup will both require more fabrication.

The plain plate of steel with a hole in it seems so easy to make (for less than the 50$ places like the above are asking) and simple to install.