My son and I built a practice horse in the coarse of one evening. It only took us about 2 hours from leaving Home Depot to something we could use. We've since "finished it out" a little nicer. It's not as fancy as some of the others on this thread, but it seems to have something the others don't. It's adjustable to any size horse. The "Stanley" saw horses are each rated to 2500 lbs and have adjustable legs. They adjust in 1 inch increments. So whether your real horse is 15 hands or 15.4, you can practice with multiple length mallets. Since there are more legs than the standard horse, it's more stable on uneven ground. And the best feature is that it's more portable. It's easily moved from one location to another. We've also made a "net" using 3" PVC pipe and an 8' X 12' canvas painters tarp suspended from the PVC with bungee straps. We've also made the PVC on the"net" so that it breaks down to 4 pieces for easy moving. Making it movable helps if you want to take it to introduce people to Polo, or your working with students at multiple locations.
Let me know if anyone would like more information about building the horse or net. firstname.lastname@example.org
Following this discussion, the designs have some flaws. 4 legs are not stable and prevent swinging or hanging in the saddle without tumbling off the horse. For stability reasons you need a tri-pod right underneath the players seat, I suggest.
Thanks for your comment. Regarding the stability of the wooden horse I built I can only tell you that even I am surprised how sturdy it is. So far I have yet to unbalance the horse while swinging or hanging out. I guess it can be done but it wouldn't be easy and it would requiere quite a lot of effort...
All the best,