Check out Montana Scabbards.


http://www.montanascabbards.com/

I have one of these, I use it to transport a compound bow. It can accomodate longer items as well. It could also accomodate a rifle or shotgun, although I have not done this yet. Email them, they will send you the mounting instructions.

I also like that fishing pole holder posted earlier, might have to get one of those too. But the scabbard pops on and off an existing rack, the fishing pole holders have to be left on, but it only looks like a few minutes to install or remove.