I would have had more steps before this but I lost the history snapshots that I saved them in.

Here, I cut out the camera and the tripod, laying them on the road background. I changed the perspective of the tripod screw to make it fit the camera better, then fixed up the edges of the camera and the red-color reflections from its previous background. I also added a grey gradient strip to the bottom of the camera to give it a better perspective.

After setting the camera on the tripod, I copied the outline of the entire thing and filled it with grey on a seperate layer. I used distortion, guassian blur, and opacity change to make it look like the camera and tripod's shadow. I also used the pen tool to lengthen the shadow's legs to make it more realistic.

This is where the squirrel idea came to mind. I moved the camera over a bit, put everything in a white frame, and put the squirrel in the shown position. I cut the arms onto a seperate layer and used the same method in step one to create a shadow for them.

Here, I merged all the layers, copied the entire picture so far, and shrunk it to fit inside the camera.

Still building on my idea, I repeated step 3 and put the picture inside another, larger camera.

Now I set the large camer on a tripod, and added another, magnified, background behind it.

Finally, I merged all layers again, and shurnk it inside the smallest visible camera of the effect. Tweaking the overall image slightly and adjusting contrast and color, I come to the final image.