Snowmobile trailer brakes might work, they are electrical and could be run off of small garden tractor batteries or small car batteries. Two modern sleds, plus the weight of the trailer could easily exceed 1,000lbs. Generally when towing a travel trailer, you'd want 15% of the weight on the hitch to prevent sway. That wouldn't work on a bike, but the placement of the weight on the trailer would still be critical. IE you wouldn't want to load the extreme rear of the trailer, which would tend to lift the rear of the bike. Lots more to think about, not worth the effort though.



However I still wouldn't ride downhill pulling it. Rent a small truck.