After being inspired by the beautiful Tau Spectre made by Proiteus, it got me thinking how we could represent the other Assassins in a Tau army. So far, I've been working on my version of the Eversor, in this case being the Kroot Aberrant, a hyper-lethal Kroot Shaper that has eaten stuff it shouldn't, and has been exiled to undertake suicide missions so as to make use of what it has become without risk of 'contamination' to the other Kindred. Parts-wise, I've used an Abhorrant Ghoul King model, with a Kroot head/hand/converted pistol, and repositioned the talons on the other to make it resemble a Kroots, to count as the neuro-gauntlet. For the 'bio-meltdown', I've used many of the Kroot grenade-ball-things, rationalising them as rigged to trigger once he dies, to ensure its taint spreads no further. I'll post some pictures soon.
As for the other Assassins, I don't have much, and obviously want to avoid "just use gue'vesa'. The Vindicare would seem to suit being a Tau operative, other than the insanely high WS and I, other than maybe being a prototype suit programmed for drone-controlled firing in close quarters.
As for the Calidus, maybe some sort of chameleonic Kroot, assisted by a prototype variant of the MV5 Stealth Drone? No real idea for this one.