Is anyone aware of a holster-type case, or anything that is designed to keep a camera easily accessible while hiking, but prevent it from swinging freely (like it does when it hangs from the neck strap)?

I have a pack with a chest strap, so anything that can attach to that might make sense. I am envisioning something that I can slide/drop the camera into that is attached to my chest, and then just lift it out when I come across something photo-worthy.

Does anything like this exist commercially? Any ideas on a DIY solution?