Vimeo member Tim Perkins looks to be a clever DIY guy. You can see him working a DIY LCD Viewfinder on his 550D. This time Tim takes a hint from a previously shared video found here: https://cheesycam.com/tripod-to-shoulder-support/ about using a tripod as a simple 'shoulder support' and finds gold in an old Bogen 3D tripod head. Using a monopod for the shoulder support, the configuration of this Bogen 3025 3D head helps position the camera to a better viewing height as well as being offset. Looks pretty stable as is, but curious if a handle, shoulder pad, and some counterweight could add some enhancements.
Not sure if it's the same, but this is the only version that shows up: