We have some rules for the Scions and Taurox here. The Taurox and Taurox Prime look really good so far, with the prime being able to take options like a Battle Cannon. Whoa. The Scions are looking good as well, and I am looking forward to these models, which seems to have some great rules attached to it.
Please remember that these are rumors, as we have not yet had an official announcement or release yet.
via an anonymous source on Faeit 212
I can confirm the reports of Astra Tempestus and Militarum leaks inside. Full stat pages and lore for the Taurox, Taurox Prime and Scions. Scions are WS 3 BS 4 Str 3 To 3 with Hot-shot Lasguns and Carapace armor. They can upgrade a number of models to have Plasma Guns, Melta Guns or Overcharged Lasguns. May take a Taurox or Chimera as dedicated transport. There is also a Scion Command Squad, but I forget the difference, they have the option of taking the Taurox Prime as dedicated transport instead. Updated: Scions along with the Scion Command Squad can take a Taurox Prime as a dedicated transport.
Taurox is approx. the cost of a lone marine in a Rhino, 11 10 10 for armor and rerolls failed terrain rolls, comes mounted with an Autocannon and can hold 10 models. Taurox Prime is approx. 2 more marines in that rhino but comes with your choice of Taurox Missile Launcher, Battle Cannon or Gatling Cannon. Same armor and transport capacity as the regular model.
Other major part of the book is an apocalypse battle report between Tau and Necrons and painting guide for those beautiful Scions.