Okay, first off, I admit I am no way up on Tau fluff in any incarnation, so there probably will be in-universe answers to all my questions, which I'd be quite interested to hear.
Anyway, am I the only one who finds it wierd that the Tau do not have any sort of titans or superheavy tanks? I mean look, Imperials, Chaos, and Orks all have them, and the Tau come up against them all pretty regularly, so I find it hard to believe that the Tau, a race which has a love of cutting-edge technology, constanty uses single-person battlesuits, and fields the largest single flyer (for which there are rules) in the 40K universe, is either unaware of the concept or have not decided to pursue the concept for a version of their own. Even the Eldar, who are a dying race, and the Tyranids, who have no technology AT ALL, have titans! It seems to me this would be a major tactical and strategic hole in the Tau armory, as all the Imperials/Orks/Chaos/what have you would have to do is bring a few Titans on-world and the Tau would have nothing to counter with. Seriously, unless there is a VERY good fluff reason, I think it's only logical that the Tau should have some Titan or Super-heavy equivalent. Maybe they'd take the concept in an entirely new and unique direction, fine by me, but they should at least have SOMETHING superheavy short of massive dropships.