Finding a good walking foot machine can indeed be challenging. Besides the Sailrite, which is excellent for heavy-duty projects, you might also consider the Juki DNU-1541. It's a top-notch walking foot machine, perfect for heavy fabrics and large projects.
Another reliable option is the Consew 206RB-5, known for its durability and consistent performance.
You can check out these models at Sewingmachinesplus: Juki DNU-1541 and Consew 206RB-5 here -
https://shrsl.com/4l5rp. Both are excellent investments for serious sewing enthusiasts. Good luck with your search!