Not sure if I am alone in this, but part of why I was drawn to the Tau Empire was in their use of drones (which also look awesome) and so I have been itching to use them in a viable way in my games, this is presently limited mostly to Shield drones alone.
I know that I am not the first to propose using Drone 'counts-as' models for the infantry in a Tau Cadre, though I think that I have a chance to justify them through both fluff and the use of accurately dimensioned models to both reduce the effect on gameplay and make them acceptable.
Now I am by no means a good writer, though I have tried to make the explanation as narrative as I could to make it as entertaining as possible for you guys, and there are some finer details such as names that I have left out as I am simply terrible at inventing them.
-----------Let the fluff begin!--------------
On the outer fringes of Tau Space a remote Water Caste trading outpost received instructions by the Tau Empire high command to arrange a trade with the Imperium of Man.
The water caste emissaries had managed to lure a Gue'la commander into the trade agreement for detailed star maps of imperial space needed for the continued expansion of the Tau Empire, this in return for an automated army of Tau drones. An Earth Caste team was deployed to the outpost to setup a research facility which would be developing the drones for the trade.
The Tau Water Caste believed the Gue'la arrogant and overconfident and that they thought Tau technology of immense strategic and technological benefits would be theirs though this trade.
The Gue'la had been convinced by the Water Caste emissaries that the Tau A.I. systems on the existing gun drones were more sophisticated and far more capable than they actually were, and that they would be provided drones to rival the military might of the Fire warriors and Battle suit variations of the Tau Cadres.
For the purpose of the demonstrations to the Gue'la the drones were to be pre-programmed for combat simulations, and the actual drones to be delivered would have oversimplified and flawed A.I. systems worse than those employed in existing Gun Drones and as such would not betray Tau tactics or advanced technology systems but would provide enough time for the Tau to relocate the outpost before the deception was discovered.
The arrangement was progressing as expected with the Gue’la remaining in close vicinity to the outpost to observe its progress, though shortly before the contract had come to completion, the Gue'la in an unexpected manoeuvre; laid siege on the Tau outpost facility. Catching the Tau off-guard they achieved swift control over the tau facility. After capturing the Tau, the exposed Gue'la renegades revealed their plans to force the Earth Caste engineers to produce untold number of drones for their obviously nefarious plans.
The Earth Caste seemingly obeying their captors had worked in secret, aided by the Gue’las very basic understanding of the Tau language and script, produced the expected drones while also making preparations to take back the outpost. Unfortunately with little to no Fire Caste surviving the initial siege and no access to either armour or armament; the plan could not rely on the normal Tau troops. This left only one, unusual, though fortunate option; which was to use the drones already produced for the Gue'la and the piloting skills of the Air Caste crews in the task of taking back their outpost.
Arrangements were made for modified remote Battlesuit control interfaces to be constructed and distributed amongst the Tau and for the outpost systems to be hacked to facilitate the plan.
The few remaining Shas were provided with the remote control systems in order to control a small number of basic drones with Pulse Rifles, though Jet pack manoeuvres had proved too much for their limited training and so only basic anti-grav propulsion could be used. For the Air Caste; taking the leap from piloting anti-grav gunships and fighters to the bigger jump pack equipped Crisis drones was simple enough, and so the plan was set.
With the groundwork in place thanks to the initial trade agreement preparations, it was not long before they were ready. While most of the Gue'la slept, the Tau initiated their attack. By restoring control of the outpost’s security bulkheads they were able to dictate flow of the battles through the tight corridors into small skirmishes where the drones would excel in killing their captors. With minimal losses to the Drones thanks to the added bonus of the surprise attack; the outpost was back in Tau control in no time at all.
This experimental Drone Army while not widely accepted within the Military of Tau Empire, does have support from a small number of Ethereals who can see the merit in its application throughout the Empire. These Ethereals have enough influence to keep the Drone Cadres deployment active, though with strict conditions imposed to ensure that their use is both limited and beneficial to the Empire.
The experimental Cadre were also provided with a small Starship outfitted with an advanced Sensor and broadcasting suite and the latest engine technology for faster and less detectable intersystem travel. Both of these features are ideally suited to the long range control of drones, and deploying the Drone Cadre to a multitude of worlds and thus; in differing environs.
The Earth Caste who had developed this system have been given permission to explore further alternatives to the standard Tau military forces, this is to ensure that they can be tested within the confines of existing Tau battle tactics and strategies. The remote control interface system has even been expanded to include Tau vehicle systems such as Hammerhead Gunships in an effort to explore their applications also.
The Water Caste were instructed to continue their role in piloting the more advanced drones such as the Crisis and Broadside along with the newer vehicle adaptations, while the Shas numbers were increased to mimic a standard Cadre for their size.
The Cadre is currently being deployed in skirmish battles across the outer fringes of Tau controlled space and continues to battle a wide variety of enemies on several different worlds, regularly sending data to be analysed by the Ethereals.
------------The fluff ends------------
UPDATE:Army so farGuide to conversions