I have several mounts on my bike for the GoPro. The main one is on the handlebars just slightly above where they turn upwards. Any higher than that and I would get vibrations.
I also have a helmet mount and one on the rear of the back seat looking backwards. I tend to do a lot of video when I'm riding in a group so I like to get some shots of the group from in front and behind.
I know you said you don't like the helmet mount, but I have to say that tends to be the most vibration free and flexible of any of the mounts I have used on the bike so far. I have the chest mount but I haven't used it. I suspect that might be pretty free of vibrations as well. The advantage of the helmet mount is it's high enough so that you're not looking at your handlebars or windshield in the frame as much. What I most like about it is I can get sideshots of places as I pass by, or other members of the group as I ride by just by turning my head. I have that mount placed in such a way that it allows me to either mount the camera looking forward or backward.
2012 Victory High Ball
Victory Stage 1 swept pipes and performance air filter
PCV and Autotune