after quite a bit of research I called ReRack and also Yakima. Both said they didn't have any other hitch bolts available based on the specs I was looking for. The closest historical Yakima bolt I could find that could have been promising seemed like Yakima model 8820052 which according to my research would have been 3-3/4 inches long.
After some pondering and reading some reviews I realized that the Yakima lock would be pretty much worthless anyhow. Given the huge size of the hitch bolt and the anti-wobble system, somebody would just need to start wrenching and the lock would most certain release like a pop-corn.
Since I have always been taught to help all walks of life, I decided to just drill the Yakima hitch lock and entirely remove its locking capabilities. I'm therefore left with the factory bolt (which fits just about with the 100Nm torque) a bridge pin, and the illusion of a hitch lock (modified). There's a little bit more to this story so read/see below.
Drilled hole all the way through to hitch pin could reach in longer (this is my NKS - No Key System):
I also needed to grind a couple of mm from the hitch side to make it fit. I painted it with black paint so it would be a bit less noticeable.
Here you see it "installed". The plastic cap was crappy and wouldn't stay on no matter how I tried. It should have been deeper with a longer plastic arm. Had I kept the lock core I would likely have put Tesa tape on it, which is what I did anyway. I figure why not, at least anyone curious would need scissors or a knife.
Seen from a bit further away. It kind of looks legit doesn't it?
I truly wasn't satisfied with this. The rack is fairly expensive to offer on a platter to potential thief, so I needed to make it a bit tricker, without having to modify the electrical connector bracket (which is what I was going to do at first).
Here's my recipe for what will make it a bit more cumbersome to remove.
1. One M16 Eye Bolt stainless steel 130mm ( I think buying a 120mm long would be better as I ended up having to shorten it a bit)
2. One M16 10.9 strength bolt length 120mm (I bought from McMaster with product code 95327A795)
3. Two narrow M16 hex nuts stainless
4. One CURT 22750 hitch cover
5. One M6 50mm stainless flat head screw (not in photo)
Additionally some Tesa tape, heat shrink and couple of stainless steel padlocks. (I spray painted the drilled holes just in case... the stainless should be good without paint but the 10.9 Zinc Yellow-Chromate Plated I felt would benefit from some paint)
My idea was to use the backside of the hitch to lock the rack in place. I figured I could do this with the help of the Yakima no-wobble hex insert, by using a longer M6 screw and then somehow preventing you couldn't "pull" the hitch out, should you be so successful to "unlock" my Yakima hitch lock NKS system.
I was going to mod a hitch cap myself but found the perfect solution on AMZ. It's a steel heavy duty cap by CURT. Anything I plan to mod I always get from their warehouse deals which I did now too. Because there isn't a ton of room between the spare tire and the back of the hitch I needed to hacksaw it shorter. This CURT cap is a beast like 2-3mm thick and it was a bit difficult to saw straight. Oh well, it didn't really matter:
I then driller a 16 mm hole in the center, filed it a bit and painted any metal that was unprotected. I didn't worry too much about the paint quality as I just needed it protected.
Here you can see my M6 screw in testing. The screw reaches to the other side (because Yakima made it so you could switch sides) but doesn't protrude.
Here you can see the eye bolt placed for testing. The Yakima hitch insert doesn't go all the way to the end, thereby leaving threads still accessible behind the CURT cap when placed.
From this angle you can see the M6 screws from the other side. This means the M6 50mm screw has "attachment" from both sides, so should someone try to pull or yank the rack out, they would definitely have some troubles (although nothing is impossible of course).
To be continued with some final installation photos.