Buckskin
I think that you would do well to make your own. When I think of Cabelas, that rigor rabbit comes to mind and it recieved poor review here for the overall preformance compared to the price. That one did not even have a shutoff (at that time) and the user had to pull the battery. Movement was reported to be Very Subtle.
The oval shaped contraption that you need for your homemade could very well be a pipe hanger that you might find at Home depot, Menards, or Lowes.
I have a 6" that is bolted to the base of my decoy but you can find these in 4"-3" & smaller. The pipehanger will accept a short piece of allthread that you can just stick into the ground.
The crossmember bolt is removed completley and your mounting holes are there.
Good luck to you, Yours is a worthwhile project.