I've been giving a bear cage some thought. My bears don't seem like they want to tear the camera up, just look at it and knock it down. They leave it alone after it's down. So I am looking at a cage that will give some protection against casual clawing, biting and a lot of impact resistance (like a football helmet).
Since it is accessed from the bottom, the bottom needs to be open.
It should be inexpensive to build and being able to build it without metl working tools is a plus for members that are tool challenged
Here's the idea and if I can get time, I'll make one next week. Painting and camo is unmentioned because everyone knows it needs to be done.
Cut a piece of 4" PVC pipe (Schedule 80 if you can get it) an inch or so longer than the camera.
Mark off for an opening for the lens and LED's (and associated sensors).
Cut the opening with a jig saw.
Mark the back for the strap slots.
Wrap the camera in a baggie and position in the case so the strap slots align and there is an inch of clearance behind the camera.
Give the back and sides a healthy squirt of expanding foam insulation.
Let it set up and use a knife to remove the excess in the bottom.
Take the camera out and you should have a custom fit.
Use the knife to open the strap holes and clean up the opening in front.
Put a cap on top, thread the strap through the case and camera and your ready to attach it to the tree.