Yes, I NEED one of those;
http://www.youtube.com/watch?v=khyZI3RK2lE
ALL my buds that carry their deer rifles in a rack behind the seat will go total green with envy if I mounted one on my pickup. Bast radius exceeding the weapon's range is a bit of a problem, but hey, Life's not perfect.
Bet you could do a bridge good and proper with one of those.