I went and got myself a second scooter. I know. I know. I can't ride two at once but I couldn't help myself. This one is a Pawtrek brand (pawtrek.ca if you want to check them out) and was made specifically for dogs to pull. I found a used one in BC for a reasonable price (although I've since found out it is missing a back fender and the rear brake had seized so I needed to get that fixed). But anyway... It's in pretty good shape. I've nicknamed her the Beast because she feels so much bigger than my other one. Ironically though she's actually 3 lbs lighter.
Summit and I took it for a test spin this morning. It wasn't his best run (maybe a bit too muggy out?) so I had to do quite a bit of work and ended up walking a fair amount. This is definitely not a scooter for dogs that don't like to pull. The plate you stand on is fairly high so you need to do some pretty big knee bends to propel yourself. It's a little awkward and takes quite a bit of effort. But it will be a great downhill scooter and it feels like very solid construction. You could definitely imagine more than one dog hooked up to it.
I also really like the front fender thing to keep the line of the wheel. It makes my other device look very mickey mouse by comparison. Although I did get a spectacular tangle somehow today and I had to actually unhook Summit so I could get it all worked out.
So I'm still reserving judgement as to which one I like better. This one definitely has great features. It just may take a little getting used to.