I have always loved the aesthetics of the Eldar Wraithlords & Wraithgaurd, but their limited mobility and range have been a deterrent for me to field them competitively. I recently decided to build some models and convert them to be used as Tau allies for my Eldar army.
The Fire Warriors (or 'Wraith Drones') are made from Necron warriors & greenstuff.
Iridium armoured Commander:
I used a Wraithlord and simply added a Jet-pack and some "missile pods".
I used Wraithgaurd, again with Jet-packs & "missile pods". The center model has the Command & Control nod and Multi-Spectrum Sensor Suite.
Used the same starting point as the Crisis suits, I added some extra armour plates and Typhoon missile launchers. I thought about using a different weapon for the Smart missiles, but since the actual Tau models use the same design for Smart missiles & Missile pods, I thought they looked fine.