I use the K9 cruiser with my dog:
It has worked great to keep my dog out from under my tires, and she also has much less leverage to pull me over. She is under 20 lbs. (a Jack Russell Terrier), but has been very peppy and likes to energetically try to dart off after things. When I used to just hold her by a leash, she would pull me over when she did this. But with the K9 cruiser she has been unable to pull me over.
The woman I bought the K9 cruiser from (2nd hand), had used it with a medium sized black lab, and told me it worked great with him too.
Not sure how well it would work with a really energetic larger dog. But if you don't find anything else, it may be worth a shot. I have been using mine for almost 10 years and love it!