Here is my attempt at scratch building a unit of Tau Sensor Towers. The actual models are from Forge World, and the rules appear in Imperial Armour Volume Three: The Taros Campaign.
My first stumbling block was getting over the destruction of a few lego pieces to make these towers... something that i found to be challenging. Once I conquered that, I was able to proceed. The base of the tower is an upside down medicine bottle with a Lego core. The top half is comprised on some bases, a few tech bits from a Power Plant Set model kit by Pegasus Hobbies and some plastic tubing.
Here are 3 complete models with a few minis for size comparison.