Those look closer to the original than anything else I found. I was looking for the Brush Gripper recently for my kayak and came across your post. Unfortunately, as many people know, the Blakemore Brush Gripper is inexplicably not being made any more. I was thinking about what could be a replacement, and read about jumper cable alligator clamps, but they don't open up wide. I thought these might work for a low budget solution. I drilled a couple holes in one handle to run a rope through for tying off to my kayak. I also drilled pilot holes in the jaw and put in a stainless steel screw in each jaw to act as a "tooth" to dig into any limb that is in the jaw. The jaws open up pretty wide as well. Haven't tried it yet, but it should hold a kayak good enough when a tree is close by.
3-1/2 in. Nylon Spring Clamp