Idea for fixing full size TC Electronic pedals to Pedaltrain pedalboard

While I was putting together my Pedaltrain pedalboard, I came up with an idea for fixing down my full size TC Electronic pedals. Below is a basic diagram of what I had in mind.

I contacted TC Electronics to find out the thread size of the thumb screw used to hold the base plate on, and was informed this is 1/4-20 (1/4" diameter, 20 threads per inch), which is the same thread that most cameras use to attach to tripods etc. 

I did try some bolts, but the main problem I came across was that that the base plate is also threaded. This is actually a good design to prevent the screw falling out when the base plate is removed, but it means a standard threaded bolt will not work, as the full thread will prevent the base plate from being tightened to the top part of the pedal.

I need to find (or have specially made) a bolt of around 25mm in length with just the top 5mm being threaded, also making sure it does not go too deep inside the pedal  and cause any damage.
Another option is to drill out the thread in the baseplate, but this will obviously devalue the pedal.

As the TC pedals stay on fairly well with Velcro supplied with the Pedaltrain (although the industrial stuff would probably be a lot better) I have decided to stay with that option for the time being, but will probably revisit this idea in the not too distant future.