Did you try looking at Eastern Woods Outdoors? They have several versions. of aiders Also, search on ETSY, there are a few different vendors selling various amsteel aiders. I have some amsteel that has a single point attachment. I think The Amsteel Guy is where who I purchased it from (ETSY). I also just recieved one (another vendor off of ETSY - cannot recall the name at this time) that has a single point attachment - more like a heavy duty 550 cord.with a rubber tube for footing. Both aiders provide options for attaching to various sticks.
I used the cable aiders from Eastern Woods Outdoors with the original single steps last year. The cable aiders pack up pretty nice and stay open so it makes them pretty easy to use once you get used to it. I was able to cut my sticks down to like 17-18" but with the cable aiders they are actually a bit longer than a full length lone wolf stick so no loss in climb height.
First picture shows them all finished up minus moving the versa button. Second picture shows when I was playing with where to cut. I ended up just cutting right below the middle step, moving the Versa button up a bit and attaching the cable aider to the bottom step bolt. Gained a couple inches over the factory length stick with the aider but lost a ton of bulk.