Moebedda, there are a few for instance the new Striker Crossbow.
gleason.chapman, I don't know where you got the idea they the only shot you should take with a PRB is broadside. I have shot diagonally through a big IL doe[ 140 #] and hit the buk behind her in the neck and took a big chunck out of his spine, dropped both deer on the spot. Any 235gr ball bullet or what ever moving at over 2000 FPS is going to do a lot of damage when applied to the right spot.
I bet some of these ideas got started by people trying to use squrril guns on deer and people that dont put half the ball weight or more in powder. Lee