My brother says he's removed stumps using a chain looped underneath the roots of the stump near the middle, and then pulling up on the chain using a "hi-lift" (4x4 truck style) jack. I tried that setup on some small stumps I had, but I couldn't get it to work for me - the jack (with only one "foot" on the ground) was wanting to torque sideways and not stay upright, so I couldn't get enough lifting force.

Your approach with the tripod looks much more effective! Thanks for sharing.