Thanks for the information and opinions. The quiver would just be for carrying spare arrows (and of course the one I hope to shoot) as it is extremely doubtful if I would ever get a second shot off at game. I guess it would be possible to get a second shot with an arrow from a crossbow, but I have never had a second shot using a vertical bow and the crossbow takes vastly more time for me to cock and fire. It has been my experience that game does not hang around after the first shot.
All of the back quivers that I have seen so far are too long for a 20" crossbow arrow, the bow mounted quiver is awkward, and I had forgotten how much noise and movement come from walking with a hip quiver. I always use a small pack when stalking game so maybe I just need to attach something to it or put an arrow box inside of it.
Hunting from a blind or stand is a no-brainer, but crawling around in the sage or slipping through the aspen trees is different altogether.
Thanks again guys.