Well the dog bone is rigid and is connects the motor to the drive shaft because the never line up properly and where the dogbone connects to the out drive is where the vibration occurs because it is a loose connection. CVD's are a little better than dogbones, but they are not without their own problems. The flex coupler is fastened very tightly at each end and the flex in the cable makes the difference where the motor and drive shaft do not line up. So there is little or no vibration because there is no loose connection
. No I have not ever made my own.
I heard of one guy with a flex cable that hit something in the water and when he got the boat in the cable looked like a spool of fishing line that got all tangled. But I hear flex cables are the way to go and are supposed to be the best for speed and low vibration.