I have been shooting 3D archery on the national level here for over 10 years. I have been running our local archery club for that long also. I have never heard of kevlar bag covers. We use the Morrel Outdoor Range bags for our archery club. We get one year out of a cover for the club, I have used my personal bag for over 5 years if you keep it out of the weather. Morrell sells replacment bags for about $20. The bags are a nylon mesh outcover with a heavy duty plastic inner liner.

Good luck on your search.