Which Zoom Gear for Tamron 28-75?

Good day,

I am looking for a zoom gear that would fit Tamron SP AF28-75/2.8 XR Di LD Aspherical (IF) Macro lens. Before I start exploring DIY options, does anyone know of any zoom gear (from Canon or Nikon) that would fit this Tamron?

The housing is Subal, CD20.

I plan to use DP-122/3 port with it, feel free to comment.

Many thanks.

I have tried the Tamron lens in the Subal housing with my D200. Ryan from Reef Photo modified a zoom gear for me but it is a real jury rig setup. The gear is split and I use a rubber band to keep it together. You can contact Ryan to find out which gear he started with. I am using the FP-90 port with an extension (I don't remember the length). I do have to say that I was not impressed with the autofocusing of the Tamron lens. You could read my thoughts about the lens here. Digital Imaging - Tamron Lens